Transport Modes and Technologies
A Walking Tour on Capacity, LOS…
Urban Transportation Planning
MIT Course 1.252j/11.380j
Fall 2006
Mikel Murga, MIT Research Associate
Urban Transportation Planning – Fall 2006
Transport Modes and Technologies
„
„
Private Transport: The automobile
Collective Transport
„
„
„
„
„
Bus
Light Rail
Rapid Transit
Taxi, CarSharing…
Non Motorized Modes
„
„
Walking
Biking
2
Urban Transportation Planning – Fall 2006
The Automobile - Infrastructure
„
Road system:
„
Mobility
Hierarchical system:
„
„
From turnpike to local street
From unimpeded movement to
access to properties (Mobility
Collectors
vs Accessibility in their lingo)
„
Uninterrupted segments:
„
„
Arterials
Turnpike with access control
Interrupted segments:
„
Traffic signals, stops…
Land Access
Locals
Figure by MIT OCW.
3
Urban Transportation Planning – Fall 2006
The Automobile – Capacity
„
The capacity of a facility 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
conditions
Highway Capacity Manual
Transportation Research Board (TRB)
HCM2000
4
Urban Transportation Planning – Fall 2006
Density Speed Relationship
„
„
„
Sf=Free flow speed
So=Optimum speed
Do=Optimum density
Dj= Jam density
Sf
Speed (mi/h)
„
So
0
Oversaturated
Flow
Do
Dj
Density (veh/mi/ln)
Speed-Density
Figure by MIT OCW, adapted from the Transportation Research Board, "Highway Capacity Manual 2000".
9
Urban Transportation Planning – Fall 2006
Speed-Flow Relationship
„
„
„
„
Sf=Free flow speed
So=Optimum speed
Do=Optimum density
Dj= Jam density
Sf
Speed (mi/h)
„
Do
So
Oversaturated
Flow
Dj
Vm= Maximum Flow
0
Flow (veh/h/ln)
Vm
Speed-Flow
Figure by MIT OCW, adapted from the Transportation Research Board, "Highway Capacity Manual 2000".
10
Urban Transportation Planning – Fall 2006
Flow-Density Relationship
„
Sf=Free flow speed
So=Optimum speed
„
Do=Optimum density
Dj= Jam density
„
Vm= Maximum Flow
„
So
Flow (veh/h/ln)
„
Vm
Sf
Oversaturated
Flow
0
Do
Dj
Density (veh/mi/ln)
Flow-Density
Figure by MIT OCW, adapted from the Transportation Research Board, "Highway Capacity Manual 2000".
11
Urban Transportation Planning – Fall 2006
Speed-Flow-Density Relationship
„
„
„
„
Sf=Free flow speed
So=Optimum speed
Do=Optimum density
Dj= Jam density
Vm= Maximum Flow
D=v/S
Do
So
0
0
So
Vm
Flow (veh/h/ln)
Vm
Flow (veh/h/ln)
„
Speed (mi/h)
Sf
0
Do
Dj
Density (veh/mi/ln)
Figure by MIT OCW, adapted from the Transportation Research Board, "Highway Capacity Manual 2000".
12
Urban Transportation Planning – Fall 2006
The Automobile – Capacity
FFS = 120 km/h
120
„
Vehicle
throughput in
uninterrumpted
flow:
„
Speeddensity
curves
1300
1450
110
1600
100
100
1750
90
80
LOS A
B
C
D
Density = 7
pc/km/ln
60
11
40
16
22
28
20
0
E
Note:
FFS= Free-flow speed
0
400
800
1200
1600
2000
2400
Flow Rate, vp (pc/h/ln)
Figure by MIT OCW, adapted from the Transportation Research Board, "Highway Capacity Manual 2000".
13
Urban Transportation Planning – Fall 2006
Speed-Flow Curves:
HCM speed-flow curve, before and after:
Human adaptation to driving in congested conditions
The original dream of ITS
BASE FREEWAY SEGMENT
Design Speed
80
4-Lanes
60 MPH
50
50 MPH
40
20
10
Unstable
Flow
*2000 pcphpi
30
*1900 pcphpi
Average Travel Speed (MPH)
120
70 MPH
0
2
(0.1)
4
(0.2)
6
(0.3)
8
(0.4)
10
(0.5)
12
(0.6)
14
(0.7)
16
(0.8)
18
(0.9)
20
(1.0)
Vol/ln (100 pcphpi)
v/c Ratio**
*capacity
**v/c ratio based on 2000 pcphpi valid only for 60- and 70-MPH design speeds
1300
1450
1600
60
1750
A
B
C
D
80
E
40
10
16
24
32
45 pcpmpl
40
20
0
0
400
800
1200
1600
2000
Average Passenger-Car Speed
(km/h)
8-Lanes
Average Passenger-Car Speed
(mph)
60
0
2400
Flow Rate (pcphpl)
Flow-Flow Speed
(mph)
> 70
65
60
55
Capacity
(pcphpl)
2400
2350
2300
2250
Note: Capacity varies by free-flow speed.
Figures by MIT OCW, adapted from the Transportation Research Board, "Highway Capacity Manual 2000".
14
14
Urban Transportation Planning – Fall 2006
Speed-Flow Curves
Unstable Flow
Stable Flow
Flows (Vehicles/hour/lane)
2500
2000
Shock Wave
Toll Range
1500
Flow at the bottleneck
1000
Undersaturated
500
Oversaturated
Density at Flow Capacity
0
0
20
40
60
80
100
120
Density (Vehicles/km/lane)
Figure by MIT OCW, adapted from the Transportation Research Board, "Highway Capacity Manual 2000".
15
Urban Transportation Planning – Fall 2006
From ideal capacity to…
„
„
„
Different vehicles have
different power to
weight ratios,
therefore…
Different gaps in front
or behind some vehicle
types
Plus:
„
„
„
„
Gradients
Widths
Weather
……
16
Urban Transportation Planning – Fall 2006
From ideal capacity to…
„
Even in
uninterrupted flow
sections, some
movements may
reduce the ideal
capacity, such as:
„
„
„
„
Merging
Diverging
Weaving
…….
17
Urban Transportation Planning – Fall 2006
Capacity under interrupted conditions…
„
„
„
Traffic signals,
roundabouts, all-stops…
Automobiles and trucks –
reaction times
Saturation, blocking
intersections (gridlock??)
18
Urban Transportation Planning – Fall 2006
The Automobile – Capacity
Urb
oad
s
Rur
oa d
s
Little nos
Vs
Fancy nos
li m
ho
es
ur
ign
al p
50-60
miles per
hour
it
{
{
ile
er m
als p
si g n
Th
ree
Thirty miles
per hour
Less than five
signals per mile
al R
Thr
ee
per signa
mil ls
e
Fo
ur
Tw -lane
roa
o-l
d
ane
roa
d
Fo
urlan
er
oad
s i gn
als
mi le
per
Fiv e
er m
Five or more
signals per mile
4
Exp
0
Two-lane road
On
8
ile
Five or more signals per mile
{
Travel time, minutes per mile
12
an R
ay
w
s
s
e
r
s6
i
m
0
le
e
sp
r
Figure by MIT OCW.
Forty miles per hour
0
400
800
1200
Vehicle volume, vehicles per hour per lane
1600
2000
From Mayer and Miller
19
Urban Transportation Planning – Fall 2006
The Automobile – Capacity
„
PEOPLE throughput :
„
„
Vehicle throughput times OCCUPANCY
Auto-occupancy (a non-technical issue)
„
„
„
„
HBW…
1.1
HBO-shop… 1.4
HBO-social… 1.7
NHB……
1.6
20
Urban Transportation Planning – Fall 2006
The Automobile – Levels-Of-Service
www.bizkaimove.com
„
„
„
The power of A to F
From spot values to travel
times
Living under saturated
conditions
21
Urban Transportation Planning – Fall 2006
The Automobile – Costs
„
Fixed Costs:
„
„
„
„
„
Vehicle purchase
Insurance
A parking spot/garage
………….
Variables Costs:
„
„
„
„
„
Gasoline
Oil and maintenance
Parking
Tolls
….
„
Ratio between Fixed and Variable Costs?
„
Why this is important?
22
Urban Transportation Planning – Fall 2006
The Automobile – Costs
„
Social costs:
„
„
„
Road construction, maintenance
Management of road system
Environmental costs:
„
„
„
„
„
„
„
„
Accidents
Health impacts
Noise (pedestrian areas)
Air pollution: cold-start, f(speed)
Land consumed
Energy
Segregation
………………
24
Urban Transportation Planning – Fall 2006
Transit - Capacity
„
People throughput:
„
„
„
Vehicle size
Headway (and fleet size)
Commercial speed
26
Urban Transportation Planning – Fall 2006
Buses - Capacity
„
Bus type and size:
„
„
No of seated spaces and no of standees
Access and ticketing:
„
„
„
„
„
„
No of doors
Easy access and egress
Access by the front door, other doors
Egress by one or two doors
Low floor
Ticket validation:
„
„
„
By the bus driver
On other machines on board
On the bus stops
27
Urban Transportation Planning – Fall 2006
Buses - Capacity
„
Capacity (Cont’d):
„
Headway: Peak-hour and off-peak
„
Commercial speed:
„
„
„
Mixed traffic
Bus lanes
Signal priority
28
Urban Transportation Planning – Fall 2006
Rail-based systems capacity
Speed profiles between
stations
7.0 2.0
113 70
Engine Governed Speed = 64 mph (103 km/h)
Speed (mph, km/h)
97 60
6.0 1.8
80 50
5.0 1.6
64 40
4.0 1.4
Speed-time
3.0 0.2
48 30
Distance-time
2.0 0.
32 20
Cruise at
55 mph
(88 km/h)
16 10
0
10
20
30
40
50
60
70
Decelerate at
2.5 mph/sec
(4 km/h/sec)
80
90
1.0 0.
100
Time (sec)
Figure by MIT OCW, adapted from the Transportation Research Board, "Highway Capacity Manual 2000".
29
Urban Transportation Planning – Fall 2006
Rail-based systems capacity
Time-Space
Diagrams
Path of front
of train
Path of rear
of train
Rate of change of slope
represents acceleration
Distance
„
Minimum safe
separation
Station
Train
=
platform length
Dwell time
(sec.)
Headway
Constant slope represents
balancing speed
Time
Figure by MIT OCW, adapted from the Transportation Research Board, "Highway Capacity Manual 2000".
30
Urban Transportation Planning – Fall 2006
Transit – LOS
„
„
„
HBW represents > 50%
Peak hours
Peak directional flows
Easy to accept overcrowding at peak to justify
service during off-peak hours
31
Urban Transportation Planning – Fall 2006
Transit - LOS
Originally, just density as for automobiles!!
BUS
RAIL
COMMENTS
LOS
ft2/p
p/seat*
A
>12.9
0.00-0.50
>19.9
0.00-0.50
No passenger need sit next
to another
B
8.6-12.9
0.51-0.75
14.0-19.9
0.51-0.75
Passengers can choose where
to sit
C
6.5-8.5
0.76-1.00
10.2-13.9
0.76-1.00
All passengers can sit
D
5.4-6.4
1.01-1.25
5.4-10.1
1.01-2.00
Comfortable standee load for
design
E
4.3-5.3
1.26-1.50
3.2-5.3
2.01-3.00
Maximum schedule load
F
<4.3
>1.50
<3.2
>3.00
Crush loads
ft2/p
p/seat*
*Approximate values for comparison LOS is based on area per passenger.
Figure by MIT OCW, adapted from the Transportation Research Board, "Highway Capacity Manual 2000".
32
Urban Transportation Planning – Fall 2006
Transit - LOS
AVAILABILITY
PASSENGER POINT OF VIEW
“QUALITY OF SERVICE”
1. Service coverage
2. Hours of service
3. Sidewalk condition
4. Park & Ride spacing
CONVENIENCE
1. Passenger loading
2. Transit/auto travel time
3. Amenities
4. Safety
Figure by MIT OCW.
33
Urban Transportation Planning – Fall 2006
Transit - LOS
Service & Performance Measures
Category
Availability
Comfort and
Convenience
Transit Stop
Route Segment
Frequency*
Hours of service*
Service coverage
Passenger loads
Accessibility
% person-minutes served
Passenger loads*
Reliability*
Transit/auto travel time
Amenities
Travel speed
Travel time
Reliability
Transit/auto
travel time
Safety
System
Accessibility
Figure by MIT OCW, adapted from the Transportation Research Board, "Highway Capacity Manual 2000".
34
Urban Transportation Planning – Fall 2006
Transit - LOS
Different points of view to judge LOS:
TRANSIT/AUTO TRAVEL TIME LOS
LOS
Travel Time Difference (min)
Comments
A
<_ 0
Faster by transit than by automobile
B
1-15
About as fast by transit as by automobile
C
16-30
Tolerable for choice riders
D
31-45
Round-trip at least an hour longer by transit
E
46-60
Tedious for all riders; may be best possible in small cities
F
>60
Unacceptable to most riders
Open to many interpretations:
Times door-to-door?
Weight factors applied to the
different time segments?
Figure by MIT OCW, adapted from the Transportation Research Board, "Highway Capacity Manual 2000".
35
Urban Transportation Planning – Fall 2006
Transit - Cost
„
Capital Costs:
„
„
„
„
>50-75 years horizon (infrastructure)
Usually not included in fare-box recovery ratio for
operating costs
12-40 years for vehicles (buses or trains)
Operating Costs:
„
Cop=Cd*veh-miles +Ct*veh-hr + Cs*fleet
(with variations for peak and off-peak)
„
Environmental Costs:
„
„
Accident rate
Noise, soot…
36
Urban Transportation Planning – Fall 2006
Buses
„
„
„
Flexibility for route adjustments
Closer stop spacing
In search of higher quality:
„
„
Low floor buses for an aging population
Bus stops:
„
„
Real time info on arrivals (and eventually downstream)
Maps, transfers, info on ticketing and validation
37
Urban Transportation Planning – Fall 2006
Viajeros anuales/310
10000
5000
2500
sube
Metro 90,000 viajeros en 11 estaciones
Rail vs Bus
Viajeros 11/12/2000
3000
1500
750
suben
BilboBus 90,000 viajeros en >180 paradas
38
Urban Transportation Planning – Fall 2006
Light Rail
„
From Rapid Rail Transit to Light
Rail:
„
„
„
„
„
Lower investments
But more exciting than buses
Mixed traffic segments
Easier to garner support for
priority
Attracts local development
39
Urban Transportation Planning – Fall 2006
Light Rail
„
Full reserved ROW or mixed traffic
40
Urban Transportation Planning – Fall 2006
Light Rail
„
Priority easily awarded…
41
Urban Transportation Planning – Fall 2006
From Public Transport
to Collective Transport
Rethinking transit:
„
„
„
„
„
„
Jitney service
Taxi-Bus
Dial-a-Ride
Taxi
Car Sharing
…….??
42
Urban Transportation Planning – Fall 2006
Some comparative little numbers
Car on city
streets
Car on
Freeway
Bus LRT
on Mixed
Traffic
1.2
1.2
40-300
40-600
140-2,200
Speed
(km/hr)
20-50
60-120
5-20
15-45
25-70
Veh/hr
600-800
1500-2200
60-80
40-90
10-40
720 to
1,050
1,800 to
2,600
2,400 to
20,000
4,000 to
20,000
10,000 to
72,000
Vehicle
occupancy
Capacity
(pers/hr)
Semi Rapid
Transit
Rapid
Transit
43
Walking – See LOS C and E per HCM
„
Capacity and
LOS
„
„
„
Moving and
Waiting
Is it
enough??
Figure by MIT OCW.
45
Urban Transportation Planning – Fall 2006
Walking – How to define LOS?
What else should come into
the picture?
•Comfort and safety
•Protection from weather
•Direct lines of sight
•Direct routing
•“Live” facades
•Conviviality
•………???
The Tube Platforms
46
Urban Transportation Planning – Fall 2006
Biking – L.O.S.
„
„
The power of a can of paint
Safety first and foremost
47
Urban Transportation Planning – Fall 2006
Biking- LOS
„
„
Again, LOS based on
throughput whether it is
one-way or two-way
Other concepts to be
included in LOS?
„
„
„
„
„
„
Inclines
safety issues
continuity
drainage
wet leaves
…………………..?
48
Urban Transportation Planning – Fall 2006
Biking: A process
49