ENG. RA'ID ARRHAIBEH
Transportation Engineering
AL-ALBAIT UNIVERSITY
ENGINEERING FACULATY
CIVIL ENGINEERING DEPARTMENT
Transportation Engineering
(0704381)
By
ENG. RA'ID ARRHAIBEH
2nd semester / 2016
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ENG. RA'ID ARRHAIBEH
Transportation Engineering
CH.1
Introduction


Transportation: movement of people and goods.
Modes of transportation:
1. Highway transportation.
2. Rail transportation.
3. Air transportation.
4. Water transportation.
5. Pipe line transportation.
6. Intelligent transportation?!

Roles of transportation in society :
A. Economically :
1. Availability of goods and services.
2. Effective use of natural resources.
3. Expansion of trade.
4. Decentralization of industries and promotion of regional
specialization.
5. Increasing large scale production and reducing the cost of
production.
6. Providing competition that produces low prices and high
quality.
Transportation level is an index of economy and development.
B. Socially :
1. Provides mobility for cultural, recreational and social
purposes.
2. Affect population distribution and housing requirements.
3. Affect employment opportunities.
C. Environmentally :
1. Its pollution affects the air, water, and land qualities which
are dangerous to human, animals and plant lives.
D. Politically :
1. Increase the ability of the country to defend itself.
2. Promotes the political unity of the nation.
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Transportation Engineering

Transportation engineering: is a branch of the engineering that deals with
planning, design and operation of the various transportation systems and their
components to achieve a safe, efficient, convenient and economical movement
of persons and goods.

Transportation problems:
1.
2.
3.
4.

System approach to problems solving:
1.
2.
3.
4.
5.

Identifying the problem.
Defining goals and objectives in solving the problems.
Searching for alternative methods of meeting the requirement.
Choosing and developing the best alternative.
Implementing its operation.
Trends in transportation development:
1.
2.
3.
4.
5.

Traffic problems ''Congestion''.
Environment problems ''Pollution ''.
Energy problems ''oil''.
Safety problems '' crashes ''.
Integration of transportation systems.
Optimization of transportation systems.
Employment of computers and new technologies.
Minimization of energy use.
Increasing efficiency of existing facilities.
Physical elements of the transportation system:
1. Travel ways: highways, waterways, railways …….etc.
2. Terminals: Airports, water ports, train stations …. Etc.
3. Carriers: automobiles, trains, airplanes, ships …. Etc.
eng. Ra'id Arrhaibeh
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Transportation Engineering
CH.2
Transportation system planning.
2.1. Introduction:

Transportation planning: is methodological process of preparing physical
facilities and services of all modes for future transportation needs.

Transportation may be considering a science that depends on ability to solve
highly technical problems.

Transportation planning must take in to consideration all modes, all traffic
(people and goods), and all social, economic, political, and environmental
factors.
2.2. Urban transportation planning (UTP):

The expansion of urban areas with population growth and economic activities
are the principal factors causing continuous increase of passenger travel.

The cost of providing the needed transportation facilities has reached an all time
high and has rapidly been increasing annually.

The urban transportation planning (UTP) process should produce a plan that
take in to account almost aspect of urban life.

The plan should be rigid enough to provide the necessary direction and control
over future growth.
See figure 2.1: an example of urban transportation planning.
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Transportation Engineering
Figure 2.1: urban transportation planning.
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Transportation Engineering
Figure 2.2: traffic flow in urban area.
2.2.1. Trends in urban transportation planning:
 Planners should consider the following classes:
1. The impact of transportation facilities on general quality of the urban
environment.
2. The impact of transportation investments on the benefit and cost distribution.
3. The impact on the spatial distribution of urban activities.
4. The impact of demanding public involvement on transportation policies and
developments.
5. The impact of transportation energy shortage on alternative transportation
policies and developments.
2.2.2. Overall urban transportation planning process:

Urban transportation includes such issues:
1. Energy shortage.
2. Environmental impact.
3. Citizen participation.
4. Social equity.
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Transportation Engineering

There are two kinds of plans:
1. Long range plan (15 years or more).
2. Short range plan (1 - 5 years).

Metropolitan Planning Organization (MPO)

Transportation Improvement Program (TIP)
organization
long range plan
planning work
programs
transportation
system managment
(TSM)
plan refinment
transportation
improvment
program
continuing process
Figure 2.3: overall transportation planning process.
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Transportation Engineering
organization
objectives
inventory
analysis
forecasts
plan
development
plan test and
evaluation
implementation
Figure 2.4: long range urban transportation planning process.
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 Objectives :
1. Minimize travel time.
2. Minimize travel cost.
3. Maximize safety.
1.
2.
3.
4.
5.
 Organization :
Centralized state staff.
Local staff.
Semi – independent organization.
Regional planning commission.
Contract study organization.
 The Staff of a planning group typically includes:
1. Transportation engineer.
2. Urban planner.
3. Geographer.
4. Economist.
5. Sociologists.
6. Systems analysts.
7. Computer specialists.
1.
2.
3.
4.
1.
2.
3.
4.
 Inventory :
Population.
Land use.
Economy activity.
Facilities.
 Analysis :
Mathematical models.
Forecasting the future target data.
Trip generation models.
Trip distribution models.
 Forecast :
Predicts future conditions in urban area (15 years).
 Plan development:
1. Several alternative plans for land use and transportation system should be
developed.
2. The transportation system should be related to the cost of construction and
operation.
3. Transportation networks are planned using the forecasted condition.
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 Plan test and evaluation:
1. Test all alternative to choose the best one.
2. The first test (safety and service).
3. The second test (economy).
 Implementation:
 After the best plan selected, the process of implementation begins.
 Continuing studies:
 Continuous studies affect the plan.
 Plans should be reviewed and updated every five years.
 Continues studies should involve :
1. Travel operation and conditions.
2. Economy.
3. Population characters.
2.2.3. Transportation system management(TSM) :

TSM projects fall in to the following major categories :
1. Traffic operation improvement programs.
2. Exclusive lanes for high occupancy vehicles (HOV).
3. Provisions for parking.
4. Pedestrian and bicycle facilities.
5. Provision for public transportation.

General TSM planning process:
1. Setting objectives.
2. Identifying problems.
3. Formulation of alternative strategies and actions.
4. Evaluation of selection strategies and actions.
5. Implementation.
6. Surveillance impact.
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
Alternative for improvements:
A. Reduce demand:
1. Pricing.
2. Peak period scheduling.
3. Ride sharing.
4. Improving public transportation.
5. Facilitating bicycle travel.
B. Capacity oriented alternatives :
1. Improving traffic operations (removal of parking).
2. Freeway operations management (access).
3. Using larger public transportation vehicles.
4. Improving pedestrian facilities.
5. Improving urban goods movement (off street loading zones).
2.2.4. Urban goods movement(UGM) planning :

Two reasons have been commonly given for the present concern with goods
movement:
1. Hidden costs concern with goods movement.
2. Using of trucks (parking, its movement with stream and air
and noise pollution).

Urban goods movement study program :
1. Objectives.
2. Design (regional, area, facilities).
3. Pilot Data collection.
4. Basic data collection.
5. Data assessment.
6. Short range goods transportation operation plan.
7. Goods movement model development.
8. Goods movement activity forecast :
- It should be specified enough to predict :
a. Quantity of goods being moved (rail or trailer).
b. Time of day movement occurs.
c. Season of year movement occurs.
d. Location in terms of geography.
9. Good assignment (time/cost).
10. Long range goods transportation system plan.
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2.3.

Statewide transportation planning (STP).
Statewide transportation planning (STP):
process those results in
recommendations leading to the attainment of set of goals that have been
dictated by public policy in the movement of persons and goods between city
pairs within the boundaries of a state.
2.3.1. Organization :
A. Modal organization :
1. Highways.
2. Airways.
3. Transit.
4. Railroads.
5. Waterways.
B. Functional organization :
1. Planning.
2. Design.
3. Constructions.
4. Safety.
5. Operations.
C. Mixed organization :
1. Highways.
2. Airways.
3. Transit.
4. Planning.
5. Administration.
2.3.2. General methodology :

Statewide transportation planning methodologies fall in to three categories:
1. Needs - Standard approach:
-
Advantage: simply done.
-
Disadvantage :
a. Intermodal connections are not identified.
b. It is not easily accomplished.
c. Benefits to users are not directly measured.
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2. Single mode simulation – evaluation approach :
-
In this approach there are essentially four steps leading to statewide plan:
a.
b.
c.
d.
Goals.
Development of plans to attain these goals.
Simulation of the present and future network.
Evaluation of the plan.
3. Multi mode simulation – evaluation approach :
-
The steps involved in this approach are these :
a. Forecast of the demands for transportation.
b. The demands are then allocated between the various
modes.
-
Advantages: greater efficiency.
Disadvantages: complex (many data may not exist).
2.3.3. Statewide transportation planning steps :
1.
2.
3.
4.
5.
6.

Defined model fall in to the following categories :
1.
2.
3.
4.
5.

Goals.
Identification of the component of the system.
Modeling of interaction between these components.
Analysis.
Evaluation.
Framework.
Travel demand, simulation and impact prediction.
Econometric, land use, activity allocation and simulation.
Resource allocation, policies and programming.
Comparison and evaluation.
Data collection.
Major purposes of the framework are:
1. System performance analysis.
2. Activity allocation analysis.
3. Cost analysis.
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2.4. Transportation demand forecasts:

Demand forecasting: an attempt to predict the future demand for transportation
services and facilities.

The work involved in transportation demand forecasts consists of both
passengers travel and goods movements.

80% of all persons trips in urban areas have either or destination at home.

60% of transit trips were for work.

The variables used in trip generation analysis are of two types:
1. Continues variables include :
a. Family income.
b. Vehicle ownership.
c. Trip length.
d. Land use density (population, employment, .etc.)
e. Geographical location.
f. Time of day.
2. Discontinuous variables include :
a. Trip purpose.
b. Land use at origin and destination.
c. Mode.

A general multiple linear regressions can be found in most statistics books
can be written in the following form:
Y = a0 + a1 x1 + a2 x2 +……..+ an xn + e
Where:
Y : dependent variable.
X1, ….., Xn : independent variables.
a’s : constants (regression coefficients).
.e : error.
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2.4.1. Modal spilt :


The purpose of modal spilt analysis is to forecast the proportion of the total
number of predicted trips to be allocated to the various transportation modes:
-
The modes of particular interests in urban planning :
1. The automobile.
2. Public transit.
-
The modes of particular interests in statewide planning :
1. Railroad.
2. Airlines.
Variables used for spilt analysis are :
1. Characteristics of the trip.
2. Characteristics of the trip maker.
3. Characteristics of the transportation system.
 Trip – end model:
𝒏
𝐐𝐢 = ∑ 𝐀𝐣 𝐅𝐢𝐣
𝒋=𝟏
Where:
Qi : Accessibility index for zone I to all other zones.
Aj : Attractions in zone j.
Fij : travel time friction (from zone I to zone j)
= 1/ ( door to door travel time)𝑏
b: an exponent that varies with trip purpose and travel time range .
n: number of zones.
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 Trip – interchange model :
1. Relative door to door Travel time:
Travel time ratio =
X1 + X2 + X3 + X4 + X5
X6 + X7 + X8
Where:
X1: Time spent in transit vehicle.
X2: Transfer time between transit vehicles.
X3: time spent waiting for transit vehicle.
X4: walking time to transit vehicle.
X5: walking time from transit vehicle.
X6: auto driving time.
X7: parking delay at destination.
X8: walking time from parking place to destination.
2. Relative travel cost :
-
The ratio of out of pocket travel cost via transit to the travel cost via auto :
Travel cost ratio =
𝑿𝟗∗𝑿𝟏𝟑
(𝑿𝟏𝟎+𝑿𝟏𝟏+𝟎.𝟓𝑿𝟏𝟐)
Where:
X9: transit fare.
X10: cost of gasoline.
X11: cost of oil change lubrication.
X12: parking cost at destination.
X13: average car occupancy
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3. Economic status of trip maker :
As the income increase, automobile owner ship increases and the use of
transit decreases.
4. Relative travel service.
Travel service ratio =
𝑿𝟐+𝑿𝟑+𝑿𝟒+𝑿𝟓
𝑿𝟕+𝑿𝟖
Where:
X2: Transfer time between transit vehicles.
X3: time spent waiting for transit vehicle.
X4: walking time to transit vehicle.
X5: walking time from transit vehicle.
X7: parking delay at destination.
X8: walking time from parking place to destination.
 Travel assignment:
T = T0 {1+0.15(𝑽/𝑪)𝟒 }
Where:
T: travel time.
T0: free flow travel time (ideal condition).
V: assigned volume.
C: capacity.
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2.5. Transportation system evaluation:

Evaluation about alternatives transportation plan based on:
1. Level of service. (LOS).
2. Objectives.

A good evaluation will ideally achieve the following ends :
1.
2.
3.
4.
5.
6.

Useful in the formulation of new plan.
Related to objectives.
Flexible.
Sensitive to cost.
Useful in the time evaluation.
Provide a workable framework of analysis.
Evaluation methods fall in to four categories:
1.
2.
3.
4.
2.6.

Pure judgments.
Engineering economy.
Willingness to pay concept.
Cost effectiveness analysis.
Transportation planning issues :
Four significant issues in today’s transportation planning :
1.
2.
3.
4.
Energy conservation.
Environmental impact.
Citizen participation.
Social equity.
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CH.3
Highway planning

Concerned with the development of the functional and economical highway
network to provide for present and future needs.
 Highway functional classification:
(1) The major roads (national roads / Principal arterials ) include:




High speeds.
Separated lanes.
No access, no signals & no at grade intersections if possible.
Interchanges are noticeable.
Class A: Trunk Roads / freeways
A national route that links two major or important cities or towns or places ( i.e Bagdad
international street ).
Class B: Regional roads / highways
Secondary national routes connecting a trunk roads or regional headquarters in a region.
(i.e. Amman – Mafraq street).
(2) The minor roads (district roads / Local roads ) include:




Lower speeds.
May be separated or not.
Access, signals, circles & at grade intersections are noticeable.
Spatial facilities are needed (bridges, tunnels, pedestrians needs, etc).
Class C: Collector roads:
-
A road linking a district headquarters (i.e. Mafraq) and a division centre
Azraq).
-
A road linking a division centre ( i.e. Azraq ) with any other division centre (i.e.
Safawi ).
-
A route linking a division centre (i.e. Mafraq ) with a ward centre ( Umejmal).
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Transportation Engineering
-
A road within urban area carrying through traffic which predominantly originates
from and destined out of the town and links with either regional or a trunk road (
URBAN ROADS)
Class D: Feeder roads:
-
A road within urban area that links a collector road and other minor road within the
vicinity and collects or distributes traffic between residential, industrial and
principal business centres CBD of the town.
-
A village access road linking wards to other wards centers (i.e. Umejmal/ Zatari ).
Class E: Community roads:
-
A road within a village or a road which links a village to a village.
Figure 3-1: Relationship of Functionally Classified Systems in Serving Traffic Mobility
and Land Access
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Figure 3-2: Hierarchy of Movement
Figure 3-3: Channelization of Trips
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Figure 3-4: Schematic Illustration of a Functionally Classified Rural Highway Network
Figure 3-5: Schematic Illustration of a Portion of a Suburban Street Network
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
-
Road inventory:
A road inventory includes :
1.
2.
3.
4.
5.
6.
7.
Location of boundary lines of all governmental units.
Cultural features adjacent to roadway.
Right of way (ROW).
Riding quality and physical condition of surface roadway (PCI).
Bridges and interchanges.
Railway crossing.
Geometric elements (sight distance, super elevation, clearance, number of
lanes, etc).
8. Services provided by highways (phones, mailbox, etc).
9. Land use information.

-
Traffic studies:
Traffic studies provide information on :
1. Characteristics of traffic flow (volume, speed, classification, etc).
2. Driver characteristics (perception reaction, ages, etc).
3. Level of service LOS and capacity of highway facilities.

Basic types of traffic counts:
1. Continuous volume counts :
-
Obtained by installing automatic detectors for counting and recording the number
of vehicles passing the location each hour or less on a daily basis throughout the
year and over number of years.
2. Seasonal volume counts :
-
Obtained by installing automatic detectors for counting and recording the number
of vehicles passing the location for seven consecutive days and repeated on
scheduled for four , six or twelve times a year.
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3. Coverage volume counts :
-
To provide volume at sufficient number of locations by installing an automatic
traffic detectors for period of 24 or 48 consecutive hours, usually once a year.
4. Classification counts :
-
In addition to the volume counts , vehicles should be classified as to type and
counted on integrated schedule , this includes weekdays and weekends
classifications ( 6:00 AM – 10:00 PM).

Financial planning studies :
-
Road use, road life, and sufficiency studies are important in determining the
continued fiscal needs, costs, and benefits of improvements.
-
Road use study: identifies the amount and characteristics of traffic using the
highway.
Road life study: determines the estimated average service life for each type of
highway surface.
Sufficiency study: evaluates the ability of the roadway to carry its quota of traffic
in safe mode.
-

-
Highway needs studies:
Providing a summary of realistic needs to inform the public of highway needs, to
aid highway administrators in programming the required projects, resources, and
funds.

Fiscal study:
-
Evaluates the present fiscal policy of the state and recommends to the legislature
an adequate and fair future policy based on highway needs.
-
It also investigates the portion of the highway tax burden that will be borne by the
land, the user, and the nonuser.
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
Highway programming :
-
Priority programming is the rational selection of proposed construction projects on
the basis of relative agency.
-
The next phase of programming is the scheduling of both time and funds of each
functional class.

Project scheduling and monitoring:
-
Identify and describe all activities that are necessary for developing the project from
start to end , including :
1. Actual work.
2. Time for approval.
3. Reviews.
4. Coordination.
-
Components of the scheduling and monitoring system:
1. Activity list.
2. A standard work flow diagram.
3. Progress reports (showing amount of accomplished work).
4. Status reports (showing relationship of progress to the
schedule).
-
Benefits from the well designed scheduling :
1.
2.
3.
4.
5.
6.
Assure scheduled dates are met.
Improve coordination between agencies and within the department.
Time saving.
Permit timely use of funds.
Allow sequencing of projects to better serve the users.
Improve response to unforeseen conditions ( funding , cut , design
changes , etc).
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CH.4
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Traffic flow characteristics
 Basic traffic variables:
1. Speed (u): km/hr or mile/hr (mph).
2. Volume (q): vehicle / hour (vph).
3. Density (k): vehicle / mile (vpm).
 Speed:
 The distance traveled by a vehicle during a unit of time (mph).
 Usually speeds take the normal probability distribution.
1. Time mean speed( spot speed) ut :
-
Average speeds of a group of vehicles at one point (using radar or very short
section).
Time mean speed is the arithmetic mean of speeds.
2. Space mean speed ( average travel speed) us :
-
It is average speeds of a group of vehicles at a long section.
Us = ∑ 𝐿𝑖 / ∑ 𝑇𝑖
Where:
Li: length of segments.
Ti: time spent in trip.
 Always us ≤ ut.
Ut = us + σs²/us
Us = ut - σt²/ut
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σs², σt²: variances of space speed and time speed respectively.
 Average running speed: only the time while the vehicle in motion (stopping
times are excluded) ‘’ another type of space mean speed.
 Volume :
-
Is the number of vehicles that pass a point a long a roadway or traffic lane per unit
of time (vpd/vph/vpm).
 Flow rate: is the equivalent hourly rate for vehicles passing a long a roadway
or for traffic during an interval less than one hour (usually 15 minutes) (vph).
 Peak hour factor (PHF): is the ratio of the peak hour volume to the peak flow
rate of flow within the hour.
 Average daily traffic (ADT): is the number of vehicles that pass on the
roadway during a period of 24 hours over certain number of days.
-
If the number of days is 365, it becomes average annual daily traffic (AADT).
 Design hourly volume (DHV): is the future hourly volume that used for
design, it is usually based on the 30th highest hourly volume of the design year.
 The design volume for the future :
(AADTf) = AADTp (1+i)ⁿ
Where:
n: design period in years.
i:growth factor.
 Headway :
 Time headway (ht): the difference between the time the front of a
vehicle arrives at a point on the highway and the front of the next vehicle
arrives at the same point in seconds.
-
Time headway distribution helps to measure platooning in the traffic stream and
can be used to obtain delay measures due to various traffic controls.
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ht=3600/q
Where:
q: flow rate (vph).
 Space headway (hs): is the distance between the front bumpers of
successive vehicles at any given instant.
hs= 5280/k
hs=ht*us*(5280/3600).
Where:
hs: average space headway (ft/veh)
us:space mean speed (sec).
5200:# of ft in mile.
3600:# of seconds in hour.
 Traffic flow relationships:
 Relationship between volume, speed and density.
 Uninterrupted flow: a vehicle traversing a section of lane or roadway is
not required to stop by any cause external to the traffic stream.
 Interrupted flow : a vehicle traversing a section of a lane or roadway is
required to stop by a cause outside the traffic stream .( due to signal ,
intersection , etc)
-
Stoppage of vehicle by a cause internal to the traffic stream doesnot constitutes
interrupted flow.
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Figure 4.1: Fundamental Diagrams of Traffic Flow.
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
Green shields Model( linear):
Where:
Us: space mean speed.
Uf: free flow speed.
Kj: jam density.
 Green bergs model (logarithmic):
Where:
Us: space mean speed.
Um: speed at qmax..
Kj: jam density.
 Traffic flow theory:
-
It is a discipline that attempts to analyze the traffic stream from a theoretical stand
point.
-
the three best known approaches are :
1. Hydrodynamic analogies: the basic assumption is that high density
traffic will behave like a continuous fluid having a certain density and
fluid velocity.
2. Car following theory: it is a microscopic approach, describes
vehicular flow as a series of inter-vehicular interaction.
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The main assumption is that a driver tries to keep the relative speed
between his vehicle and the vehicle in front of him as small as possible.
3. Queuing theory: it is a microscopic model; it is concerned with
waiting queues and there delays.
The model consists of three elements:
a. Arrival characteristics (input).
b. Service characteristic (out put).
c. Queue discipline (FIFO,LIFO)
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CH.5
Highway capacity and level of service (LOS)
-
-

Highway capacity is a quantitative and qualitative measure which permits
evaluation of both the adequacy and the quality of vehicle service being
provided.

The capacity of a facility:
It is the maximum hourly rate at which persons or vehicles reasonably can be
expected to traverse a point or a uniform section of a lane or roadway during a given
time period under prevailing roadway , traffic , and control condition.
Any change in the prevailing conditions changes the capacity of the facility.

Factors affecting highway capacity:
1. Roadway conditions: lane width, lateral clearance, surface conditions,
grades, etc.
2. Traffic conditions: % trucks, traffic interruptions, etc.

Ideal conditions :
-
Under ideal conditions highway can accommodate maximum traffic volume.
-
Ideal roadway conditions assume :
1. Good weather.
2. Good pavement conditions.
3. Familiar users.
4. Uninterrupted flow.
5. Only passenger cars in traffic stream.
6. Lane width (3.6m) , shoulder width (1.8m).
7. Level terrain.
8. No access.
9. Obstructions distance ≥1.8m.
10. Free flow speed of 100 km/h for multilane highway.
11. No passing zones on 2lane/2way.
12. No traffic obstructions (conflict).
…etc.
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
-
Highest capacity under ideal conditions according to HCM :
Freeways: 2400 pc/h/lane.
Multilane highway: 2200 pc/h/lane.
2lane/2way: 2800 vph for both directions.

Highway users judge the quality of service through the following:
1.
2.
3.
4.
5.
6.

Travel speed.
Traffic interruptions.
Freedom to maneuver.
Safety.
Driving comfort.
Operating cost.
Etc.
Level of service LOS:
-
It is a quality measure describing operational conditions within a traffic stream,
generally in terms of such service measures as speed and travel time, freedom of
maneuver, traffic interruptions, and comfort.
-
6 LOS
-
The service flow rates generally are based on 15-minutes period, typically, the
hourly service flow rate is defined as four times the peak 15 minute volume.
-
Most design or planning efforts typically use future service flow rate at LOS C or
LOS D, to ensure an acceptable operating service for facility users.
-
Travel speed and density on freeways, delay at signalized intersections, and walking
speed for pedestrians are examples of performance measures that characterize
flow conditions on a facility.
-
For LOS F, it is difficult to predict flow due to stop and start conditions.

-
A
F
The service flow rate :
It is the maximum hourly rate at which persons or vehicles can be expected to
traverse a point or uniform segment of a lane or roadway during a given period
under prevailing roadway, traffic, and control conditions while maintaining a
designated level of service.
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Level of Service A: Free-flow operations in which vehicles are completely unimpeded
in their ability to maneuver. Under these conditions, motorists experience a high level
of physical and psychological comfort, and the effects of incidents or point breakdowns
are easily absorbed.
Level of Service B: Traffic is moving under reasonably free-flow conditions, and freeflow speeds are sustained. The ability to maneuver within the traffic stream is only
slightly restricted. A high level of physical and psychological comfort is provided and
the effects of minor incidents and point breakdowns are easily absorbed.
Level of Service C: Speeds are at or near the free-flow speed, but freedom to maneuver
is noticeably restricted. Lane changes require more care and vigilance by the driver.
When minor incidents occur, local deterioration in service will be substantial. Queues
may be expected to form behind any significant blockage.
Level of Service D: Speeds can begin to decline slightly and density increases more
quickly with increasing flows. Freedom to maneuver is more noticeably limited, and
drivers experience reduced physical and psychological comfort. Vehicle spacing
average 165 ft (8 car lengths) and maximum density is 35 pc/mi/ln. Because there is so
little space to absorb disruptions, minor incidents can be expected to create queuing.
Level of Service E: Operations are volatile because there are virtually no useable gaps.
Maneuvers such as lane changes or merging of traffic from entrance ramps will result
in a disturbance of the traffic stream. Minor incidents result in immediate and extensive
queuing. Capacity is reached at its highest density value of 45 pc/mi/ln.
Level of Service F: Operation is under breakdown conditions in vehicular flow. These
conditions prevail in queues behind freeway sections experiencing temporary or longterm reductions in capacity. The flow conditions are such that the number of vehicles
that can pass a point is less than the number of vehicles arriving upstream of the point
or at merging or weaving areas where the number of vehicles arriving is greater than
the number discharged. Breakdown occurs when the ratio of forecasted demand to
capacity exceeds 1.00.
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Figure 5.1: Levels of Service for Freeways.
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CH.6
Uniform Traffic Laws and Control Devices

Manual on uniform traffic control devices (MUTCD)

Main purposes of traffic control devices (TCD):
1. Increase safety.
2. Increase capacity.
3. Reduce delay.

Main highway traffic control devices (TCD):
1. Markings.
2. Signs.
3. Signals.

To be effective, traffic control device should meet the following basic
requirements:
1.
2.
3.
4.
5.

Fulfill a need.
Command attention.
Convey a clear and simple meaning.
Command respect from road users.
Give a adequate time for proper responds.
TCD can be effective through :
1. Design.
2. Placement.
3. Operation.
4. Maintenance.
5. Uniformity.
 Pavement markings:
-
Used to regulate and guide the traffic providing channels to different movements.
-
Advantages :
-
1. No physical obstruction to traffic.
2. Low cost.
3. Ease of removal when required.
Disadvantages :
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1.
2.
3.
4.
-
TCD uses :
1.
2.
3.
4.
5.
6.
7.
8.
9.
-
Obliterated easily by snow or soil.
Wearing out rapidly.
No physical separation of conflicting movements.
Not effective under low visibility.
Centerlines.
Lane lines.
Pavement edge lines.
No passing zones.
Lane reduction transitions.
Stop lines.
Crosswalks.
Parking spaces.
Curb marking.
Etc.
Object markings :
 Any dangerous obstruction close to the traveled way should be marked.
(Bridge, trees, islands, signal support, etc)
 Marking shapes and color: diagonal black and white strips.
-
Delineators :
 Reflecting devices mounted at the road to indicate the roadway
alignment especially at horizontal curves.
-
Studs (cat eyes):
 At ground reflecting devices used as centerlines, lanelines, and
pavement edges.
Figure 6.1: an example of pavement markings.
 Signs:
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-
Signs Classification :
a. Regulatory signs: provide information about laws and regulation.
1. Right of way signs.
2. Speed signs.
3. Movement signs.
4. Parking signs.
5. Pedestrian signs.
Figure 6.2: an example of regulatory signs.
b. Warning signs: warn the drivers where caution is required.
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1. Indicate changes in horizontal alignment.
2. Indicate intersections.
3. Warn that the drivers should expect TCD.
4. Warn converging traffic lanes.
5. Indicate narrow roadways.
6. Indicate changes in highway geometry.
7. Advise of unusual grades.
8. Advice at grade rail crossing.
9. Indicate sudden change in surface condition.
10. Indicate unexpected entrances and crossings.
11. Other signs (speed limit, animal crossing, etc).
Figure 6.3: an example of warning signs.
c. Guide signs: guide the drivers where to find routes and locate items.
1. Route markers.
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2. Direction and destination markers.
3. Information signs.
Figure 6.4: an example of guide signs.
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Figure 6.5: Examples, influence of cut height and slope on traversability
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
Color code:
1.
2.
3.
4.
5.
6.
7.
8.
Black: regulation.
White: regulation.
Yellow: warning.
Red: stop or prohibition.
Green: direction guidance.
Orange: temporary traffic control.
Brown: recreational and cultural interest area guidance.
Blue: road user services guidance, tourist’s information and evacuation routes.
Etc.

Channelization :
-
Using islands and lane markings to separate the intersecting, merging diverging,
waving, and turning movements.
-
Advantages :
1.
2.
3.
4.
5.
6.

Separate through movement from opposite movements.
Control the merging, diverging and crossing movements.
Reduce paved areas.
Refuge Island for pedestrian.
Provide a space for signs.
Provide storage lanes.
TCD and conflict points:
-
TCD are used to reduce or/and organize the conflict points at intersections.
-
Three type of conflicts are :
1. Merging.
2. Diverging.
3. Crossing.
-
Number of conflicts depends on :
1. Number of approaches.
2. Turning movements.
3. Type of TCD.
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Figure 6.6: conflict points at intersection (4-leg).
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CH.7
Traffic System Control

Intersection types:
1. at grade intersection.
2. Grade separated interchange.
3. Grade separations without ramps.
Figure 7.1: 4-leg intersections.
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Figure 7.2: some types of interchanges.

-
Uses of interchanges:
Trumpet and Y: 3-leg intersection.
Diamond: Major X minor.
Full cloverleaf: Major X Major.
Directional: freeway X freeway.
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
Intersection control types:
1. Yield signs: slow down to give right of way, stopping not mandatory.
 Used at minor roads with speed limit ≥ 10 mph and right turn lanes
without acceleration lanes.
2. Stop signs: stopping is mandatory.
 Used at intersections with restricted view or high volumes or accidents.
 Two ways stop TWS: traffic on minor approaches stop.
 All Way Stop AWS: traffic on all approaches stop, used when traffic on
all approaches are approximately equal.
3. Signals: used when necessary (8 warrants).
 Advantages of signals:
1. Orderly and coordinate movement of traffic.
2. Increases safety.
 Signal types :
1. Pre-timed: fixed time, use dials.
2. Semi-actuated: provide green time to the major street until detectors on
minor street approaches actuate demand for signal. Provide minimum and
maximum green for minor and minimum green for major.
3. Fully - actuated: detectors on all approaches, minimum and maximum
green time on all approaches.
4. Volume-density: green times and cycle lengths are readjusted constantly,
sensing devices measure volume and density.

Signal warrants:
 A traffic control signal should be installed :
1. Unless one or more of (MUTCD) warrants are met.
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2. Engineering studies indicates that installing a signal will improve the
overall safety or operation of the intersection.
3. If it will seriously disturb progressive traffic flow.









Traffic signal warrants:
Warrant 1:8-hour vehicular volume.
Warrant 2: 4-hour vehicular volume.
Warrant 3: peak hour.
Warrant 4: pedestrian volume.
Warrant 5: school crossing.
Warrant 6: coordinated signal system.
Warrant 7: crash experience.
Warrant 8: roadway network.
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CH.8
Design of highway facilities
 Highway design standards:
-
Design standards depend on functional classes.
 Freeways: high speeds, wide lanes, mostly straight horizontal and
vertical alignment.
 Collector and local streets: low speeds, high access density, etc.
 Design level of service LOS:
-
Table 8.1: appropriate level of service for specifid combinations of area and terrain
types.
Functional class Rural level Rural rolling Rural mountainous Urban and sub urban
freeway
B
B
C
C
arterial
B
B
C
C
collector
C
C
D
D
local
D
D
D
D
 Geometric design elements:
1.
2.
3.
4.
5.
Alignments (horizontal / plan and vertical / profile).
Cross section.
Sight distance (stopping sight distance SSD and passing sight distance PSD).
Intersections and interchanges.
Other facilities (drainage, medians, parking, pedestrian and bicycle needs, and
buses lane).

Horizontal alignment:
Figure 8.1: Elements of a circular curve.
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-
Consists of series of tangents connected by circular curves.
The alignments must be continues, without sudden changes which may be dangers
to drivers.
In the design of highway curves , it is necessary to consider :
1. Design speed (V).
2. Degree of curvature (radius R).
3. Super elevation (e).
𝐑𝐦𝐢𝐧 = (
𝐕²
)
𝟏𝟐𝟕(𝐞 + 𝐟)
Where:
Rmin: Minimum Radius for Road Curves (m).
V: Design Speed (km/h).
e: Cross fall of road or the maximum super elevation (%/100). The value of e may
represent the simple removal of adverse cross fall or include super elevation (e =
positive for cross slopes sloping down towards the inside of the curve and otherwise
negative).
f: Coefficient of side friction force developed between the vehicle’s tires and road
pavement (see Table 8.2 ).
Table 8.2: Side friction factors for different design speeds
Design Speed (km/h)
Limiting value of (f)
30
0.17
40
0.17
50
0.16
60
0.15
70
0.14
80
0.14
90
0.13
100
0.12
110
0.11
120
0.09
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Figure 8.2: central force
-
Vehicles enter or leave circular curves following transition paths, at high speeds the
transition paths may mix lanes and create hazardous conditions.
-
Spiral curves are used to connect tangents with simple curves, which help in
widening the pavement around the circular curve and give a desirable arrangement
for super elevation run off.
Figure 8.3: super elevation
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Figure 8.4: elements of super elevation.
-
The length of super elevation run-off is given by the formula:
Lr = (
Where:
(w ∗ n1) ∗ ed
) ∗ (bw)
Δs
Lr : Length of super elevation runoff (m).
ed : Value of design super elevation in percent.
Δs : rate of change of super elevation (relative gradient) in percentage as given in Table
3.3
w : width of one traffic lane, m.
n1 : number of lanes rotated.
bw : adjustment factor for number of lanes rotated (Table 3.4)
Table 8.3: Maximum and Minimum rate of Change of Super elevation.
Design
Speed
Km/h
Max. Δs
(%)
Min. Δs
(%)
30
40
50
60
70
80
90
100
110
120
0.75
0.70
0.65
0.60
0.55
0.50
0.47
0.44
0.41
0.38
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.3
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Table 8.4: Adjustment Factors for Number of Lanes Rotated
-
Number of lanes Rotated
Adjustment Factor
1
2
3
1.00
0.75
0.67
Length Increase Relative to OneLane Rotated (=n1bw)
1.0
1.5
2.0
The minimum length of tangent run out is calculated by the formula below:
Where:
e0
Lt = ( ) ∗ (Lr)
ed
Lt : minimum length of tangent run out, m.
Lr : Length of super elevation runoff.
ed : Value of design super elevation in percent, %.
e0 : Normal Cross Slope in percent, %.
Ls = Lr + Lt
Where:
Ls : minimum length of spiral curve(m).
Lr : minimum length of tangent run off, m.
Lt : minimum length of tangent run out, m.
Or
𝐿𝑠 =
Where:
Ls : minimum length of spiral curve(ft).
V: Design Speed (mile/h).
R: Radius for Road Curves (ft).
C: constant rainging from 1 to 3.
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
-
Vertical alignments :
It is a series of a tangents grades connected by parabolic vertical curves.
Figure 8.5: Vertical Curves in roads
Table 8.5: Maximum Grades (%)
Terrain
40
50
60
Flat
5
Rolling
7
6
8
Mountainous 10
9
8
Design Speed (km/h)
70
80
90
100
5
4
3.5
3
6
5
4.5
7
7
110
3
120
3
Table 8.6: Recommended standards for maximum grades, %
Type of terrain
Freeways
Rural highways Urban highways
Level
3-4
3-5
5-8
rolling
4-5
5–6
6-9
mountainous
5-6
5-8
8 - 11
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-
In general: maximum grade = 8%.
-
the vertical curves lengths are related to K by the formula:
L = KA
Where:
L = Length of vertical curve.
K = Rate of vertical Curvature (the required length of crest/ sag curve to a 1% change
in gradients)
A = Algebraic difference between the gradients (g2-g1)

Sight Distance SD:
-
It is the length of highway a head which is visible to the drivers.
-
Stopping sight distance SSD: is the sum of the perception reaction distance and
the breaking distance.
 The minimum stopping sight distance a long highway should be long
enough to permit a driver traveling at the design speed to stop in order to
avoid hitting an object on the road.
𝒅 = 𝟏. 𝟒𝟕 𝑽 ∗ 𝒕 +
Where:
V : speed (mph)
t: reaction time (sec) = 2.5 sec.
f:coefficient of skidding friction.
g:grade %.
54
𝑽²
𝟑𝟎(𝒇 ± 𝒈)
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Table 8.7: SSD on level terrain.
Table 8.8: SSD on grade.
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-
Passing Sight Distance (PSD): is the minimum distance a head that must be clear
to the driver on a passing maneuver.
 PSD is important in 2lane/2 way.
 The passing sight distance is generally determined by a formula with four
components, as follows:
d1 = initial maneuver distance, including a time for perception and reaction.
d2 = distance during which passing vehicle is in the opposing lane.
d3 = clearance distance between vehicles at the end of the maneuver.
d4 = distance traversed by the opposing vehicle.
Figure 8.6: Passing Sight Distances.
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Figure 8.7: Passing Sight Distances elements.
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Figure 8.8: Passing Sight Distances for design of 2lane/2way.

Pavement cross sections:
-
Lane: 3.25m — 3.75 m (3.2 m — 3.6 m AASHTOO).
 Number of lanes ( approximate) : N = DDHV / SFLi
DDHV = AADT * K * D
Where:
DDHV: directional design hourly volume (vehicle/hour).
K: % of AADT in peak hour (0.1 for urban and 0.15 – 0.20 for rural).
D: directional factor (0.5 for urban and 0.65 for rural).
SFLi : lane service flow rate ( table 3.24)
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Table 8.9: Level-of-Service Criteria for Basic Freeway Sections
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-
Shoulder : ½ lane width (1.8 m)
-
Advantages of shoulder :
1. Increase safety.
2. Increase capacity.
3. Used as emergency lane.
4. Protect pavement layer from water.
Etc.
Parking lanes ( on street parking) : 2.5 m – 3.0 m
Used in urban area.
-
Sidewalks : 1.5 m – 2.0 m
-
 Used in dense pedestrian areas.
Median ( in divided highway) : 1.5m – 20.0 m
 Median barriers are used with narrow median.
 Advantages of wide medians:
1.
2.
3.
4.
-
Future extension of lanes.
Maintain vegetation.
Reduce headlight glare of opposing traffic.
Different elevation of the two adjacent roads that may
provide lower cost and separate super elevation.
Etc.
Right Of Way ROW: make it as wide as possible, spatially in the rural areas.
 For 2lane/2way: (20 m – 30 m).
 for freeways: ( 60 – 100 m )
-
pavement slopes ( crown):(2.0% -- 2.5 % for lane & 3.0 % – 3.5 % for shoulder )
 Used for drainage purposes.
-
Road sides slopes :
 Side slop: next to the shoulder (6:1 --- 1.5:1) depending on the height of
cutting.
 Back slope: next to the ditch in the cut section (4:1 – 1.5:1) depending on
the soil properties.
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Figure 8.9: Typical cross section for a dual carriageway, design class 1
Figure 8.10: Typical cross sections for two lane paved roads.
-
Curbs: used in urban and suburban roadways.
 If it closes to traffic lane: Low, flat, lip type, 45º.
 If it far from traffic lane: barrier type, 90º.
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-
Ditches: should be located beyond the shoulder limits and below pavement layers.
 Types: U-shape & V-shape.
 U-shape is safer and need less maintenance.
-
Other elements:
 Bike lane.
 Mail box turnouts.
 Border strip for utilities.

Guardrails: used for fills having more than 2.5 m height and sharper than 3:1
slopes.
 When using guardrails, shoulder width should be extended 0.5 m or
2 ft more.
 Types of guardrails :
1. Steel (W-beam or Box).
2. Concrete.

Automobile parking facilities:
-
Curb on street parking should be prohibited at:
1. Major Street.
2. Bus stops.
3. Pedestrian cross walk.
4. Fire plugs (5m).
5. Vicinity of intersection :
 UN signalized intersection: 10 m.
 Signalized intersection: 20 m.
 Driveways: 5m.
-
Parallel parking is preferred over angled parking for safety.
Angled parking is preferred over parallel parking for capacity.
Use diagonal 45º.
-
Marking the parking makes its use more efficient.
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 Off – street parking:
-
Most important aspect is the choice of site.
-
Maximum walking distance accepted by parkers depends on :
1. Trip purpose: (office workers 150 m, shoppers 50 m).
2. City size: the smaller the city the shorter the accepted walking distance.
3. Cost of parking.
-
Parkers prefer parking facilities that are :
1. Close to destination.
2. Easily accessible.
3. Safe.
4. Cost little or no money.
-
Lay out of parking lots:
 Types :
1. 90º parking with two way traffic.
2. 45º - 75º parking with one way traffic.
 Stall width: 3.0 m.
 Stall depth: 6.0 m.
-
Parking dimensions are functions of the parking angles.
-
Best parking lay out depends on :
1.
2.
3.
4.
Size and shape of the area.
Type of facilities (self parking, attendant).
Type of parker (short term, long term).
Type of operation (one way, two ways).
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Figure 8.11: parking stall layout elements.
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
-
Garage design criteria:
Single lane entrances and exits with 3.6m.
Ceiling height of 2.5 m.
Access between floors by :
1. Ramp: Rmin = 9m, width = 3.6 m.
2. Sloped floors: 4% for self parking, 10% for attendant.
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CH.9
Highway safety

Elements of highway system:
1. Road.
2. Vehicle.
3. Driver.
4. Pedestrian.

-
Current procedures for identifying accident – prone locations:
Due to limited budgets, it is essential that agencies making highway safety
improvements direct resources to real problem locations.
-
Procedures for identifying accident :
1. Spot maps.
 Marking the location of each accident on a map.
 A map hung on a wall with pins to mark accidents is useful.
 Computer graphics easily produce spot maps.
Figure 9.1: Collision Diagram
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2. Accidents frequencies.
 Identify accident – prone locations through lists of locations (spot
sections, intersections, etc) ranked by the number of reported
accidents.
3. Accident rates.
-
Use data for last 5 years.
A. For Highway section :
-
Accident rates in terms of accidents per 100 million vehicle miles using the formula
:
𝑹𝑺𝑬𝑪 =
𝟏𝟎𝟎𝟎𝟎𝟎𝟎𝟎𝟎𝑨
𝟑𝟔𝟓 ∗ 𝑻 ∗ 𝑽 ∗ 𝑳
Where:
RSEC: accident rate for the section per 100 MVM.
A: number of reported accidents.
T: time frame of the analysis, years.
V: AADT.
L: length of section, mile.
-
B. For intersection :
Accident rate in terms of accidents per 1 million entering vehicles ( per MEV) from
the equation:
𝑹𝑴𝑬𝑽 =
𝟏𝟎𝟎𝟎𝟎𝟎𝟎𝑨
𝟑𝟔𝟓 ∗ 𝑻 ∗ 𝑽
Where:
RMEV: accident rate for the intersection per 1 MVE.
A: number of reported accidents.
T: time frame of the analysis, years.
V: AADT.
4. Accounting for severity.
 Fatal accident F= 12 points (or 9.5 points, some country 8 points).
 Injury accidents I= 3 points (or 3.5 points).
 Equivalent Property Damage Only EPDO = 1 point.
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Table 9.1: National Highway Traffic Safety Administration Summary of Accident Unit
Costs, 2000
5. Classic statistical method.
-
After ranking locations of interest by frequency or rate (adjusting for severity if
necessary), analysts could choose the top n locations for further detailed analysis.
-
Analysts will select a location if it satisfies the inequality :
OBi ˃ XA + K*S
Where:
OB: accident frequency or rate at location i.
XA: mean frequency or rate for all locations under consideration.
K: constant corresponding to level of confidence.
S: sample standard deviation for all locations.
Table 9.2: Constant Corresponding to Level of Confidence.
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Example : Baghdad freeway has an accident rate of 210 accidents per 100 million
vehicle miles (MVM) , the mean accident rate for all sections in the jurisdiction is 89
per 100 MVM and the standard deviation corresponding to this mean rate is 64 per 100
million MVM , should an analyst flag Baghdad street as hazardous with 90%
confidence?
Solution:
OBi ˃ XA + K*S
300˃95 + (1.645 * 70)
210 ˃ 190
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CH.10
Urban Mass Transit UMT
 Most recent urban public transport systems are:
1.
2.
3.
4.
Articulated bus.
Bus rapid transit BRT.
Light rail transit LRT.
Metro.
 Advantages of mass transit:
1.
2.
3.
4.
5.
High capacity.
Energy efficiency.
Less pollution.
Reduce congestion.
Lower cost.
 System classification:
A. By route type :
1. Cross town.
2. Radial.
3. Circumferential.
4. Grid.
B. By service :
1.
2.
3.
4.
Residential collection system.
Feeder system.
Line-haul system.
Down town distribution system.
 Performance measures:
1.
2.
3.
4.
5.
Cost efficiency (cost per passenger mile).
Labor productivity (passenger miles per employee).
Energy efficiency (energy consumption per passenger mile).
Accessibility (within walking distance).
Quality of service (LOS: A-F based on travel time, % of trip on
time).
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 System economics:
-
There are five categories of system economics :
1. Operating wages and benefits (straight time and overtime
wages).
2. Transportation cost (fuel, maintenance, etc).
3. Vehicle costs (insurance, license, office expenditures, etc).
4. Fixed overhead costs (managements, office expenditures, etc).
5. Capital costs (depreciation…).
 Transit financing:
1.
2.
3.
4.
General taxes (property, sales, and income taxes).
Auto disincentive taxes (gasoline, registration, parking taxes).
Direct benefit financing (local government subsides).
Non-transit related taxes (cigarette taxes).
 Transit rate:
F=Fb + K*N
Where:
F: fare to be paid.
Fb: base fare.
K: increment in price per zone.
N: number of zones crossed.
 Types of bus service:
1. Local bus transit: provides service on city streets and subject to interferences
from other traffic.
2. Rapid bus transit: has exclusive right of way and can maintain higher speeds.
3. Subscription bus service: works on a daily or weekly basis.
4. Dial – A- bus system: users call a central computer and request a bus, used
for elderly and handicapped.
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 System components:
-
A. Bus transit vehicle:
The transit bus has a seat capacity of ten or more passengers.
For local busses, the area also provides space for standees in case of high demand.
-
Types of vehicles :
1.
2.
3.
4.
Minibus (L= 6 m– 6.5 m, no. of seats = 16-24).
Conventional (L= 10m-13m, no. of seats = 35-54).
Articulated (L= 18m-20m, no. of seats = 35-70).
Double deck (L=8m-10m, no. of seats = 50-90).
B. Bus travel way :
1. Shared travel way (affected by traffic delay and congestion).
2. Reserved lanes (separated from other types of vehicles).
3. Bus streets.
4. Traffic signal preemption.
-
Warrants for reserved lanes :
1. Freeways: at least 300 busses during peak hour.
2. Urban streets: at least 30 busses during peak hour.
C. Bus stop:
-
-
-
The main goals in planning and designing bus stops:
1. Provide direct bus access to and from express roads and bus
ways.
2. Minimize bus layover in order to maximize berth capacity.
3. Separate loading from unloading operations.
4. Utilize each berth by minimizing the number of different routes.
5. Minimize walking distance to walking bus lines.
6. Utilize automobile parking to reduce bus mileage in low density
residential areas.
Maximum spacing of stops for local bus system is about 0.5 miles (750 m).
Bus stops ( according to their location from intersections ) are :
1. Near side (the bus is going to turn right on the same
intersection).
2. Far side (the bus is going to turn left on the next intersection).
3. Midblock (the bus is going straight or intersection stops are not
possible).
Special bus stop turnout is provided on freeways near park and ride services.
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-
Bus stop may have only a sign, a bench, or a shelter.
Shelters may have advertising, telephones, scheduling information, etc.
 Operating characteristics:
A. Service routes:
-
The factors that affect bus demand are :
1. Density of residential areas.
2. Non residential areas size and density.
3. Distance between residential and non residential areas.
4. Average auto ownership.
5. Level of service of the bus system.
6. Bus fares.
-
The factors that affect the bus route configurations:
1. The overall system service.
2. The geography of the area.
3. Streets available for bus use.
4. Other competing transit services in the area.
-
Route layouts:
1. Radial.
2. Circumferential.
3. Grid.
B. Service frequency :
f=n/N
Where:
f:frequency ( busses / hour).
n:demand for service(passenger / hour).
N: maximum number of passengers per bus ( bus capacity).
h= T a + T b
h:minimum headway between busses in minutes.
Ta: average dwell time for alighting in seconds.
Tb: average dwell time for boarding in seconds.
-
Dwell time: the total amount of time a bus spends at a bus stop.
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Tb=Aa+C……………for lighting only.
Tb=Bb+C……………for boarding only.
a,b : average alighting , boarding service time per passenger in
seconds.
A,B : alighting , boarding passengers per bus in peak 15 min.
C: clearance time between successive busses in seconds.
a= 1.5 - - 2.5 seconds.
b= 2.5 – 3.5 seconds for fare collected by the drivers.
= 1.5 – 2.5 seconds for fare collected before boarding.
C=15 seconds.
C. Service capacity :
-
The factors that affect the capacity of a bus way are:
1. Road way capacity.
2. Bus station platform capacity.
3. Headway.
4. Vehicle capacity : determined by:
a. Seating capacity (number of seats).
b. Standing capacity (number of standing considering health
and safety standards).
Ct = Ca + z*Cb
Rc = 60 Ct / h
Where:
Ct: total vehicle capacity.
Ca: vehicle seating capacity.
Cb: ultimate vehicle standing capacity.
Z: allowable fraction of ultimate vehicle standing capacity.
Rc: maximum route capacity ( passengers / hour).
h: minimum head way in minutes.
D. Scheduling :
-
Where vehicle headways are greater than 10 minutes, the headway must be in 5
minutes increments (15, 20, 25, 30, etc).
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CH.11
Air Transportation
 Air craft characteristics:
1. Weight: affect the design of pavement thickness for run way, taxi way, and
aprons.
2. Size: the aircraft length, width, and height affect the size of airport facilities
(width of runway and taxiway, parking areas, hangers and maintenance sheds,
turning radii, etc).
3. Capacity: passengers and cargo capacity affect the design of ground services
(terminal size, baggage handling facilities, departure lounges, gate positions,
etc).
4. Range: affect the frequency of operations.
Figure 11.1: runway and taxiway.
 Runway length:
-
Until 1950’s piston aircraft needed runway length of 8000 ft.
Large jet aircrafts needed runway length of 12000 ft.
Jet aircrafts needed longer runways because :
1. Low thrust characteristics at low speeds.
2. Swept wings with high loadings.
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-
Using turbofans reduced the need for long runways since it increases the thrust
capability. (In addition, turbofans decrease the noise levels).
 Passenger capacity:
-
-
Increasing passenger capacity led to pedestrian congestions in air passenger
terminals (departure and arrival lounges, baggage handling and access and egress
procedures).
Higher capacity aircrafts are motivated by reducing operating costs (labor, fuel,
etc).
 Cruising speed:
-
B747: 550 mph.
Concorde: 1450 mph.
Future goal: 3000 mph, but this is not efficient due to the high cost and low fuel
efficiency.
 Future trends in air transport characteristics:
-
The trend is to increase capacity and speed, but increasing in speed is not safe and
is not economical.
 Airport planning and layout:
-
Airport demand depends on :
1. Population and their density.
2. Economic character.
3. Proximity to other airports.
-
Demand is referred to as annual passenger flow that is corrected to monthly, daily,
peak day, and peak hour flow.
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 Selection of airport site:
desk study
( plans,wind direction , costs , etc)
phisical inspections
( alternative sites)
evaluation and recommendations
( 10 criteria)
Figure 11.2: selection of airport site procedure given by Federal airports association
FAA.
-
Evaluation and recommendation criteria :
1. Convenience to users (center of most cities).
2. Availability of land and its cost.
3. Design and layout of the airport (orientation).
4. Airspace obstruction (other airport, towers, etc).
5. Engineering factors (level topography).
6. Social and environment factors (noise and pollution).
7. Availability of utilities (water, electricity, etc).
8. Atmospheric conditions (fog, snow, dust, etc).
9. Hazard of birds.
10. Coordination with other airports.
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 Runway orientation :
Figure 11.3: runway orientation.
-
Aircrafts may not maneuver safely on a runway when the wind contains a large
component at right angle to the direction of travel (crosswind).
Cross wind speed component should be ≤ certain value according to the type of
aircraft expected to use the airport.
FAA standards: 95% of the time cross wind should be less than the maximum
allowable.
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Figure 11.4: wind speed and direction instrument.
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
-
Wind Rose Method:
A graphical procedure utilizing a wind rose is used to determine the best runway
orientation.
10 years of wind observations are required.
Wind data are arranged according to velocity, direction and frequency .
Figure 11.5: wind rose method.
-
Steps to determine the best runway orientation and to determine the percentage
of time that orientation conforms to the cross-wind standards:
1.
Place the template on the wind rose so that the middle line passes through the
center of the wind rose.
2. Rotate the template to get the maximum sum of percentages between the outside
lines of the template.
3. Read the bearing of runway on the outer scale of the wind rose, beneath the
centerline of the template.
4. Check cross-wind.
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-
Example: The table indicates the % of time wind velocity can be expected.
Wind
Direction
N
NNE
NE
ENE
E
ESE
SE
SSE
S
SSW
SW
WSW
W
WNW
NW
NNW
CALMS
TOTAL
Typical Wind Data
Percentage of Winds
5-15mph
4.8
3.7
1.5
2.3
2.4
5
6.4
7.3
4.4
2.6
1.6
3.1
1.9
5.8
4.8
7.8
15-25mph
1.3
0.8
0.1
0.3
0.4
1.1
3.2
7.7
2.2
0.9
0.1
0.4
0.3
2.6
2.4
4.9
0-5 MPH
81
25-30mph
0.1
0.1
0.3
0.1
0.2
0.2
0.3
total
6.2
4.5
1.6
2.6
2.8
6.1
9.7
15.3
6.7
3.5
1.7
3.5
2.2
8.6
7.4
13.0
4.6
100%
ENG. RA'ID ARRHAIBEH
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
Objects affecting navigable airspace:
-
Obstacles should be removed or clearly marked.
-
FAA regulation defines imaginary surfaces free of objects hazardous to air
navigation.
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Figure 11.7: obstructions standard in the vicinity of airports.

Obstacle height:
 Within 3 nautical miles a height of 200 ft above the established
airport level (longest runway ˃ 3200 ft) and the height increases
100 ft for every 1 nautical mile up to max 500 ft.
-
Another methods:
1. Horizontal surface: horizontal plane 150 ft above airport elevation (radius=
5000 ft).
2. Conical surface: a surface extending outward and upward from horizontal
surface at a slope of 20:1 for a horizontal distance of 4000 ft.
3. Primary surface: has the same elevation of the centerline of the runway and
extend 200 ft beyond each end of the runway (width 250 to 500 ft based on type
of runway).
4. Approach surface: inner edge of approach surface is the same width as the
primary surface but it extends outward and upward with a slope based on runway
type.
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5. Transitional surface: surfaces with slope extend with a slope of 7: 1 from the
sides of the primary surfaces to the sides of the approach surfaces.
Figure 11.8: airway clearance requirements.

Runway capacity:
-
Saturation capacity: maximum number of aircraft operations that can be
handled during a given period under conditions of continues demand.
-
Runway capacity depends on:
1.
Aircraft mix.
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2.
3.
4.
5.
Weather.
Visual flight rules VFR or instrument flight rules IFR.
Layout and design of the system.
Arrival/departure ratio.
-
Air craft mix:
1. Class A: small engine aircraft (wt ≤ 12500 lb).
2. Class B: small multi engine aircraft (wt ≤ 12500 lb).
3. Class C: large aircraft (12500 lb ˂ wt ≤ 300000lb).
4. Class D: heavy aircraft (wt ˃ 300000lb).
-
Mix index = C% + 3*D%
Table 11.1: airport capacities for long range planning purposes.
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
-
Runway configuration:
Best run way configuration depends on :
1.
2.
3.
4.
5.
-
Safety requirements.
Wind direction.
Topography.
Available space shape and a mount.
Airport design.
Types of runway configuration :
1. Single.
2. Non-intersecting divergent runway.
3. Parallel runway.
4. Offset parallel.
5. Intersecting runway.
.
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Figure 11.9: Types of runway configuration:
Figure 11.10: single runway.
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Figure 11.11: Non-intersecting divergent runway.
Figure 11.12: parallel runway.
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Figure 11.13: offset parallel runway.
Figure 11.14: intersecting runway.
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
Airport passenger terminal area:
-
Terminal area includes:
1. Automobile parking lots.
2. Aircraft parking aprons.
3. Passenger terminal buildings.
4. Facilities for intra and inter terminal transportation.
-
Terminal area should accommodate peak hour traffic to avoid delay.

Types of airports:
1. Utility airports: includes small buildings for commercial activities
and maintenance and administration buildings for pilots, passengers
and visitors.
2. Hub airports: large airports.
Figure 11.15: typical air trip.
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 Terminal planning and design:
-
Involves four organizations:
1. Airport owner: financing.
2. Federal government: immigration, customs, and
inspection.
3. Airlines: each has its own needs.
4. Concessionaires: restaurants, shops, car rentals, etc.
health
 Terminal layout concepts:
-
Design objectives :
1. Adequate space.
2. Flexibility to cope with technology.
3. Reduce walking distances for pedestrians and taxiing requirements
for aircrafts.
4. Obtain revenues.
5. Acceptable working environment for airport and walking staff.
 Terminal layout schemes:
1.
2.
3.
4.
5.
6.
7.
Frontal (queen alia).
Pier finger.
Satellite (Los Angeles).
Remote apron (Jeddah).
Remote pier (linear).
Remote pier (cruciform), (Atlanta).
Gate arrival (Chicago).
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Figure 11.16: Terminal layout schemes.
 Intra and inter terminal transportation:
-
Results of a study:
1. Average walking distance to nearest gate = 565 ft.
2. Average walking distance to farthest gate = 1342 ft.
3. Average walking distance between airlines = 4091 ft.
-
Large airports use: moving sidewalks, vehicle system, and mobile lounges.
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 Automotive parking and circulation needs:
-
More than 50 % of passengers use cars to or from airports.
Parking spacing should be within 400 ft from terminal building (maximum 1000
ft).
Multi level parking structures are used.
-
Parking users:
1.
2.
3.
4.
5.
Passengers.
Visitors brining passengers.
Employees.
Business callers.
Rental cars and taxis.
-
Spaces for employees can be far by providing shuttle busses.
-
Vehicular circulation:
1. Counter clockwise.
2. One way.
3. No at grade intersection.
-
Curb parking should be provided for pickup and drop off.
 Terminal apron space requirements:
-
Apron: an area for parking of aircraft.
-
Size of gate positions depends on size and maneuverability of aircraft.
-
Number of gate ( stand ) positions depends on :
1. The peak volume of aircraft to be served.
2. How long each aircraft occupies a gate position.
-
Gate occupancy time depends on :
1.
2.
3.
4.
5.
Type of air craft.
Number of passengers.
Amount of baggage.
Magnitude and nature of other services required.
Efficiency of apron personal.
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-
Required number of stands ( USA standards) , n = V*T/ U
Where:
V: design hour volume for departures or arrivals (aircraft / hour).
T: weighted mean stand occupancy (hour).
U: utilization factors (0.6 – 0.8).
-
Required number of stands ( European standards) , n = M*Q*T
Where:
M: design hour volume for departures or arrivals (aircraft / hour).
Q: proportions of arrivals to total movements.
T: mean stand occupancy (hour).
-
Future stands ={ ( present stands – 2 ) *
-
Aircraft parking configurations:
1.
2.
3.
4.
5.
𝑓𝑢𝑡𝑢𝑟𝑒 𝑝𝑎𝑠𝑠𝑒𝑛𝑔𝑒𝑟𝑠
𝑝𝑟𝑒𝑠𝑒𝑛𝑡 𝑝𝑎𝑠𝑠𝑒𝑛𝑔𝑒𝑟𝑠
Perpendicular Nose in.
Perpendicular Nose out.
Parallel.
Angled Nose in.
Angled Nose out.
Figure 11.17: aircraft parking types.
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 Terminal building:
-
Space should be provided for :
1. Facilities for passengers : tickets sales , waiting areas , baggage
checking and calming , security , flight information , telephones ,
gift shops , car rentals , medical services , hotels , motels ,
restaurants , barbers , shops , etc.
2. Aircraft operations: communication center, operation rooms for
crews.
3. Airport operations and maintenance: air traffic control, ground
traffic control, airport administration, FAA offices, airport
maintenance, fire protection, utilities.
 Design considerations:
-
Terminal building should be flexible for future expansion (staged design, using
partitions, etc).
Use multi level buildings for passenger’s circulation.
Figure 11.18: apron terminal area.
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Figure 11.19: general aviation terminal area.
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Figure 11.20: Passenger flow diagram for U.S. domestic arrivals and
departures
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CH.12
Rail Transportation
 Service characteristics of rail transportation :
1.
2.
3.
4.
5.


Service safety.
Travel speed.
Performance reliability.
Comfort and convenience.
Travel cost.
Rail road locomotives:
-
Engine types:
1. Electric.
2. Diesel-electric.
3. Steam.
4. Gas-turbine-electric.
5. Diesel-hydraulic.
Etc.
-
Intra city (urban) rail service: closely spaced stations require the train to
accelerate and decelerate between stations causing delay and low speed.
-
Intercity rail service: large distances between stations help the train to keep
higher speeds without the need to accelerate or decelerate.
Factors affecting the transit car selection:
1.
2.
3.
4.
-
Acceleration rate.
Station spacing.
Speed capability.
Overall line- haul travel speeds.
Maximum allowable acceleration rate :
 8 ft/s² (all seated).
 5 ft/s² (standees are expected).
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 Rail way design:
-
The rail travel way (track) consists of two steel rails at fixed distance a part.
-
The rails are anchored to cross ties which are set in a bed of gravel.
-
+Generally railroads are built at land surface.
-
At crossing waterways and valleys, and through mountains bridges and tunnels
are used.
 Route selection:
-
Avoid places to frequent slides and rock falls.
River and stream crossings should be made as far upstream as conditions permit.
Number of crossings of highways and other rail lines should be minimized.
Provide good drainage.
 Soil study and sub grade:
-
Soil analysis is related to the design of rail road travel ways.
Sub grade is the foundation on which the roadway is constructed.
Soils represent the material of which the road bed is constructed.
 Rail way cross section:
-
Sub grade width:
 In fill areas: 22 ft (height ˂ 20 ft).
24 ft (20 ≤ height ≤ 50 ft).
26 ft (height ˃ 50 ft).
 In cut area: 30 – 40 ft (may be more in open area).
 Cross section elements:
1. Ballast.
-
Ballast is the material in which the track structure is imbedded for the purpose
of holding the track to line and grade.
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-
Material: crushed stone and washed river gravel.
-
Grain size: 1.5 – 1.75 inches.
-
Sub ballast: used when ballast material is expensive, there is a short of supply,
or very low sub grade quality exists.
-
Ballast depth: 6 – 30 inches depending on wheel loading, traffic density and
speed, type and condition of foundation.
-
Sub ballast depth: 12 inches.
-
Ballast quality standards should be tested for :
-
a.
b.
c.
d.
Wear resistance.
Cleanness.
Frost resistance.
Unit weight.
a.
b.
c.
d.
e.
Distribute wheel loading.
Anchor the track.
Provide immediate drainage.
Minimize dust.
Inhibits vegetation.
Ballast is used for :
2. Cross ties (sleepers).
-
Materials :
a. Treated wood.
b. Concrete (pre-stressed and reinforced).
-
Section: (6 x 6 inch) up to (7 x 9 inches).
-
Length: 8, 8.5 and 9 ft.
-
Average spacing: 21 inch.
-
Function of crossties:
a. Spreading loads to ballast.
b. Providing correct gage between rails.
c. Anchoring the track.
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d. Making the needed adjustments to vertical profile.
3. Rails.
-
Continuous inverted T-shape steel beam.
-
Function: transmits loads to crossties via tie plates and fastenings.
-
Length: 1440 ft (in the past 39 ft).
-
Advantages of long rails:
a. Less maintenance costs.
b. Higher speeds are allowed.
c. Less damage.
d. Smoother ride.
-
Rail gage: 4 ft + 8.5 inch.
4. Tie plates.
-
Laid on the crossties under rails.
-
Dimensions: (7 inch – 8 inch) x (10 inch – 14 inch) x (0.56 inch – 1 inch).
-
Functions :
a. Preventing damage to the wood crossties by distributing the wheel
loads.
b. Holding the rails to proper gage.
c. Offsetting the outward lateral thrust of the wheel loads.
5. Fastenings.
-
Used to anchor the tie plates to the crossties.
6. Rail anchors.
-
Used to anchor the rails to the ballast in order to reduce the longitudinal
movements and control the temperature expansions of rails.
7. Rail joints.
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-
Functions:
a. Provide smooth continuity of rail ends.
b. Transfer the wheel loads between rail ends.
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CH.13
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Water Transportation
 Introduction:
-
Water mode of transportation was available 8000 years ago.
-
99% of overseas freight transportation use ships because:
1. It has the lowest cost.
2. It is the most suitable mode for commodities that have large
volumes and heavy weights.
-
In water transportation, time should not be critical.
-
Example of cargo:
1. Petroleum products.
2. Coal.
3. Machinery.
4. Vehicles and parts.
5. Wood.
6. Containers (large scale).
 Waterborne vessels (ships):
-
Trend: towards automation.
-
Automation advantages:
1. More efficiency.
2. Less labor costs.
-
Automation disadvantages:
1. Low adaptability to other uses.
2. Risks the rapid technological obsolescence.
 Principle classes of service for shipping industry:
1. Linear service: predetermined schedules between specific
ports.
2. Non-linear service: no schedules, chartering and special
voyages.
3. Tanker service: for the carriage of liquid cargo.

Passenger ships:
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Transportation Engineering
-
Few passenger ships remain in service due its low speeds compared with other
modes of transportation.
Types of passenger ships:
1. Passenger ferries (for short distance).
2. Cruising ships (for recreation).

General cargo ships:
- Trend is increasing the size and speed.

Bulk carriers:
- Used for carrying the ore and coal.

Tankers:
- Liquid cargo (oil, asphalt, gasoline, chemicals, etc.).
- Trends: increase the capacity (from 600000 ton to 1000000 ton).

Spatial ships:
- Container ships: carries containers with standard size. (Example: 8*8*20 ft).
- Barge carrying ships: carries its loading and unloading equipments.
- Roll on – roll off ships: carries loaded pickups and trucks.
 Ships characteristics:
1. Dimensions:
 Length: governs the length and layout of the sea port terminal.
 Beam: governs the width of channels and basins, and cargo
handling equipments.
 Draft: governs the depths of channels, basins, and ports.
2.
3.
4.
5.
6.
7.
Cargo carrying capacity.
Cargo handling (crane, pumps).
Types of cargo.
Shape.
Mooring equipment.
Maneuverability.
 Design of harbors:
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
-
Harbor: partially enclosed water area to protect ships from waves and winds
and control the erosion of the beach.
-
Port: portion of the harbor for commercial activities.
Environmental consideration:
-

Winds:
-

Cause horizontal forces on all structures at the boundaries of the port.
Current :
-

Cause horizontal forces on all structures above water level.
Waves :
-

Protection should be provided against biological (termites attack wood) and
chemical (rust of steel) factors.
Similar to waves but has lower speed.
Tide :
-
Rising and falling of water surface ( caused by the gravitational attractions of the
moon and the sun.
 Classes of harbors:
-
According to structures:
1. Natural: formed in bays and inlets.
2. Artificial: using artificial structures.
-
According to uses :
1. Commercial: for trade.
2. Military: navy.
 Desirable features of harbor site:
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1.
2.
3.
4.
5.
6.
Sufficient depth (21 – 37 ft up to 94 ft for tankers).
Secure anchorage.
Adequate anchorage area.
Narrow channel entrance.
Protection against wave action.
Good soil conditions (firm and cohesive).

shape and size of anchorage area depend on :
1. Maximum number of ships to be served.
2. Ship sizes.
3. Mooring method (single or tow anchors).
4. Maneuverability requirements.
5. Topography.

Rule of thumb:
Width of entrance = length of largest ship.

Breakwaters and jetties:
-
-
Breakwaters: built parallel to the shorelines to protect the shore area from
waves.
Jutties: built perpendicular to the shoreline to maintain a protected entrance
channel.
Breakwater types:
1. Rubble mound (large stone): natural or artificial (concrete units).
2. Wall breakwaters : made of :
a. Timber cribs filled with large stones.
b. Concrete caissons filled with sand.
c. Sheet pilling.
3. Composite: both 1 and 2.

The number of berths required to be determined using the Poisson
probability distribution:
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Transportation Engineering
𝑷𝒏 = (𝑻 (𝒏 )ʱ𝒆−𝒏 ) / h!

Where:
Pn : probability of the number of the units of time that h ships are
present during T time – units.
n: the average number of ships present.
e: 2.71828
The annual port capacity Q in tons is given by the following equation:
Q = Nb * R * T (% occupancy / 100)
Where:
Nb: number of berths.
R: annual average cargo handling rate per berth (tons/day).
T: time period, usually 365 days.
eng. Ra'id Arrhaibeh
CH.14
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Transportation Engineering
Intelligent Transportation System (ITS)
 Intelligent Vehicle Highway Systems (IVHS)
-
The ITS started by IVHS.
-
Goal: to improve transportation safety and efficiency using the current and
emerging technologies (information processing, communications, control,
electronics, etc).
-
IVHS: using the available technologies to improve the efficiency and safety of
traffic operation by automating the driving of the vehicles on the highways
through automation of the longitudinal control, communication and steering
providing very short and safe headway.
-
Produced headways are expected to be as short as 0.5 sec providing lane
capacity of 7200 vph.
 Intelligent transportation systems (ITS):
-
ITS: used to benefits from the new technologies in all transportation systems.
ITS has the following major areas:
1. Travel management:
a. Advanced Traffic Management Systems (ATMS): network
detection, traffic assignment, real time adaptive signals
control, incident detection, ramp metering, electronic toll
collection, congestion management.
b. Advanced Traffic Information Systems ( ATIS):
 Navigation information by in car screen or radio.
 Changeable messages signs (speed, weather, engine
conditions, vehicle locations, route guidance, shops,
etc).
c. Advanced Public Transportation Systems (APTS):
 Traveler information (TV, internet).
 Electronic fare payment.
 Priority at signals.
 Automatic vehicle location (AVL).
d. Advanced Rural Transportation Systems (ARTS):
 Traveler information for rural roads.
 Safety and incident detection.
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 Medical and emergency services.
2. Commercial Vehicle Operations (CVO):
 One time stopping for information and weight check.
 Technology desired to reduce cost , enhance driver
safety , and improve service to customers.
3. Advanced Vehicle Control and Safety Systems (AVCSS):
 Better control of vehicle, such as antilock brakes, and
automatic cruise control.
 In future detect the edge of the lane or other vehicles and
alert the driver or make steering or baking corrections
automatically.
 In future, allow reduced vehicle spacing and increase
capacity.
4. Automated Highway Systems (AHS):
 Another name for IVHS based on automated driving
(easily controlled at roadway segments but not at
intersections).
 Challenges and problems for AHS (IVHS) :
1. Cost.
2. Legal issues: who is responsible for accidents?
3. Performance of old cars.
eng. Ra'id Arrhaibeh
‫جامعة ال البيت االردنية‬
109
‫‪ENG. RA'ID ARRHAIBEH‬‬
‫‪Transportation Engineering‬‬
‫كلية الهندسة‬
‫قسم الهندسة المدنية‬
‫هـندســــــــــة المواصــــــالت‬
‫)‪(0704381‬‬
‫للمهندس ‪ :‬رائد محمد الرحيبة‬
‫الفصل الدراسي الثاني ‪5102 – 5102 /‬‬
‫الطبعة الثانية‬
‫‪110‬‬