TM and TDM required reading/G Frame
The World Bank
Distance Learning Course in Urban Planning
Module 4: Traffic Management and Transport Demand Management
Gladys Frame, Consultant Traffic Engineer
1.
2.
3.
4.
5.
6.
7.
8.
9.
Introduction
What is Traffic Management?
The Pre-Conditions for Successful Traffic Management
The Benefits of Traffic Management
Institutional Requirements for Traffic Management
Traffic Management Strategies and Techniques
Transport Demand Management (TDM) Strategies
Transport Demand Management Techniques and Measures
Elective Reading
1.
Introduction
1.1
Traffic management and transport demand management form key elements of World Bank
urban transport projects in developing countries.
1.2
Usually traffic management components in Bank urban transport projects include institutional
development, training, road safety, enforcement and road user education proposals in addition to
traffic engineering and traffic demand management techniques. Traffic management component
are typically linked to the construction of significant road infrastructure.
1.3
This module introduces the student to the context of traffic management in urban planning; the
principles and practice of traffic management and its key elements and benefits; the institutional
requirements for traffic management and key traffic management techniques. The module also
covers transport demand management strategies, techniques and measures and the role of traffic
management in implementing transport demand management strategies.
2.
What is Traffic Management?
2.1
Traffic management and the urban environment: Traffic management measures are not only
an essential complement to new road and bridge construction but also play a key role in
achieving a better quality of life for all. Without them, new roads cannot interface properly with
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the existing road network nor can the existing network function efficiently. New construction
can provide access to new developments, provide replacement traffic capacity for through and
local routes to allow environmental improvements and pedestrian facilities to be provided, and
provide or upgrade missing links in a functional road hierarchy. But the provision of more
traffic capacity within an urban area could also stimulate more vehicle trips, lengthen journey
distances, encourage diversion to cars from other modes such as public transport and bicycles,
and create the same level of congestion over a larger area. Traffic management plays a key role
in helping to avoid these problems.
2.2
Managing the use of road space and its surroundings for all road users: Urban roads are
key physical elements of the urban environment and influence its layout, shape, form,
appearance and use. Historically, public roads were developed for the movement of people and
goods and for the general public to gain access to adjacent properties. However, these uses have
expanded over time to encompass the need to load and unload goods, to park vehicles and to
allow many non-transport uses such as walking, trading, entertainment, ceremonies, playing,
shopping and activities spilling over from adjacent premises. This mixture of uses has led to the
development of techniques for managing the use of road space and its surroundings for all road
users including pedestrians, public transport passengers and cyclists as well as private motor
vehicle users. This is essentially what the term 'traffic management' means. The context for the
use of traffic management is illustrated in Figure 2.1 below.
Figure 2.1: The Context of Traffic Management
2.3
Maximizing the efficiency and safety of the road network: Traffic management techniques
generally do not include major new road construction but may involve more modest physical
road works. Traffic management focuses on maximizing the efficiency and safety of new and
existing roads.
2.4
Broad scope of traffic management: The term 'traffic management' has a broader scope not
confined to the traditionally narrow focus of traffic operations and enforcement seen in many
developing countries where traffic management is often the responsibility of the Traffic Police.
The term 'traffic management' covers: the development of traffic management strategies and
policies within the context of broader transport policies; the planning, design and implementation
of comprehensive schemes and individual measures; operation and enforcement; and, finally,
evaluation and monitoring of schemes and measures.
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3.
The Pre-Conditions for Successful Traffic Management
3.1
In developed countries, traffic management is well developed and techniques have evolved over
many years in the context of moderate traffic growth. The trends in the United Kingdom (UK)
for example, illustrate the initial focus on physical design ('Roads in Urban Areas', 1966),
developing into consideration of managing traffic on roads ('Roads and Traffic in Urban Areas',
1987), and now focusing on the environmental impact of traffic ('Transport in the Urban
Environment', 1997).
3.2
While traffic management techniques are wide ranging, they cannot solve some of the
fundamental problems associated with poor development control and land use planning, underdeveloped transport planning, lack of coherent data, and poor road user behavior, although they
can mitigate some of the symptoms of these deficiencies. It is important to realize the
limitations of traffic management, particularly in developing countries which do not have the
context of a sound institutional and legal framework, a functional road hierarchy, development
control strategies and transport planning techniques of developed countries.
3.3
Land use planning and road network development: Local authorities often have high and
sometimes unrealistic expectations of what traffic management can achieve and what problems
traffic management can solve. In order for traffic management measures to realize their full
benefits there needs to be a coherent system of land use planning and road network development.
Land uses which are incompatible with a functional road hierarchy need to be relocated. New
buildings and their activities need to be compatible with the planned road functions. This is a long
term strategy achieved step by step by adherence to the Master Plan, Structure Plans and Local
Plans.
3.4
A functional road hierarchy forms a framework for both guiding and implementing all
strategies, including traffic management ones. Traffic management strategies and techniques
can be used to reinforce and improve a desired hierarchy, for example, by rationalising existing
mixed use of a street and upgrading/downgrading it by traffic management techniques so that its
operating characteristics and the road environment reflect its desired status in the hierarchy.
Mixed use of roads will always occur but the aim should be to reinforce the desired primary
functions of each road through traffic management techniques in association with other transport
measures
3.5
Road user behavior affects how traffic management measures achieve their objectives. The
extent to which drivers, cyclists, pedestrians and passengers obey traffic signs and road markings
and use traffic facilities can have a significant effect on the benefits of traffic management.
Improvements in road user behavior can be achieved in the short to medium term by education and
training and the provision of better traffic facilities to encourage correct behavior – i.e. 'natural'
enforcement by good design. In the longer term the strengthening of traffic law and its
enforcement to improve compliance with traffic regulations can create a mature culture of good
road user behavior.
3.6
A comprehensive approach:
In many cities in developing countries traffic management
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techniques typically tend to respond to problems as they occur rather than be planned to avoid
such problems occurring. This approach may have been be considered by local leaders to be
unavoidable due to the rapid economic expansion of their cities and the growth in private motor
vehicles. Techniques tend to be reactive, and site and situation specific, and not a series of
coordinated area-wide measures. However, for traffic management to be successful, schemes
need to be developed in a comprehensive way using a series of integrated and coordinated
measures such as targeting a specific area or a specific problem area-wide. There is a need to
'think big' but pay attention to the details – the design, implementation, maintenance and
enforcement of traffic management – otherwise traffic management can be brought into disrepute.
3.7
The status and image of traffic management: Finally, traffic management needs to be seen to
be as prestigious and important as new road and bridge infrastructure. The status and image of
traffic management needs to be high and this can be achieved by investing more resources in
traffic management; utilizing the latest technology in conjunction with underlying key techniques;
and by investing in training and enhancing the status of traffic professionals.
4.
The Benefits of Traffic Management
4.1
Traffic management measures are not only an essential complement to new road and bridge
construction but also play a key role in achieving a better quality of life for all. Without them,
new roads cannot interface properly with the existing road network nor can the existing network
function efficiently
4.2
Short-to-medium timeframe: Traffic management measures are appropriate in a short-tomedium term timeframe given the rapidly changing cityscapes of cities in developing countries..
Typically, schemes should be seen in the context of a rolling program of 3 - 5 years duration; they
can be reviewed and updated regularly to ensure that the benefits are not superseded by new
construction. However, as part of a broader strategy, traffic management strategies have to be
practicable in the long term.
4.3
Relatively low cost: Traffic management schemes incur relatively low costs compared to major
road infrastructure. The cost of catering for traffic demand by using the existing street network is
considerably lower than building new infrastructure, if demand can be catered for sufficiently.
Techniques such as Area Traffic Control (ATC), junction improvements, segregation of traffic
modes, for example, may be able to cater for demand without the need for viaduct construction or
road widening. How much can be achieved by traffic management depends on the integration and
coordination of a whole range of measures which together with commitment and enforcement,
form a coherent and effective techniques.
4.4
Flexibility: Traffic management has the flexibility and ability to cater for all traffic modes,
particularly those which are not catered for by new infrastructure. New road building usually
favors motor vehicles and particularly the private car at the expense of other modes. So, although
public transport can benefit from improved road building, special bus priority measures will be
also be required. Traffic management techniques can also effectively cater for pedestrians and
bicycles.
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4.5
Improving the environment: Traffic management can be used to improve environmental
conditions. Such techniques involve minimum severance and visual intrusion; restrictions on
motor traffic can reduce air and noise pollution; and the creation of pedestrianized areas can
improve amenities for all.
4.6
Quantifying the benefits of traffic management: It is often difficult to quantify the benefits of
traffic management schemes or even specific traffic management techniques. Many benefits are
qualitative. However, for vehicles. traffic management measures are usually evaluated by using
Moving Car Surveys to get data on journey time, journey speeds, time spent stopped, time spent
delayed and, as a proxy for fuel consumption, the number of stops. For pedestrians, the
reduction in walking time to public transport and pedestrian hubs, the reduction in severance of
walking routes and the increase in safe and convenient crossing facilities would be looked at.
For example, to evaluate pedestrian safety, accident and casualty numbers, type and severity
would be looked at. For public transport (PT) passengers, PT occupancy, journey times, PT
reliability and ease of interchange would all be assessed. Safety and environmental parameters
would also be assessed: accident and casualty numbers and severity; noise and air pollution; and
severance and visual intrusion.
4.7
Area Traffic Control (ATC): For example, the benefits of Area Traffic Control (ATC)
systems have been evaluated worldwide in several countries, typically by using both Moving Car
Surveys and the system software. Worldwide, ATC has been shown to reduce fuel consumption
by 4- 20% and journey time by 12 – 22%. In UK cities, delay has been reduced by up to 48%
during peak hours. In China in Beijing and Shanghai, delay has been reduced by up to 32%
during peak hours, journey time by 16%. and the number of stops by up to 33%.
5.
Institutional Requirements for Traffic Management
5.1
The traffic management process: There are three key stages of the traffic management process
that have to be considered with regard to the institutional requirements for traffic management:



traffic management policies and strategies
traffic management planning, design and implementation
traffic management operations and enforcement
5.2
The traffic management process in many developing countries is often undeveloped and
uncoordinated, an traffic management policies and strategies can be undefined. Traffic
management policies and strategies should ideally be developed within the context of an already
developed overall transport policy for a city or a region. However, in many developing
countries, transport planning is in its infancy and a more realistic approach may need to be taken
whereby existing good practice in traffic management is encouraged and guided in a step-bystep process towards a more comprehensive approach. This is typically in addition to
institutional development to create the most appropriate institutional environment for the
development of comprehensive traffic management strategies and techniques.
5.3
Traffic management in many developing countries is often the responsibility of the Traffic
Police and, as such, its focus tends to be on enforcement. There can be little experience or
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expertise in traffic management planning and design and no agency responsible for this. For
example, the design and implementation of small physical measures (such as channelisation
islands) often falls into an institutional gap whereby such measures are too insignificant for
Highway Design Agencies to deal with yet outwith the scope of the Traffic Police.
5.4
In most cities urban transport administration is a function of city government. Most
governments have created specialised transport departments to deal with urban transport
development and management and the scope of these departments varies. Urban transport can
be divided into planning and management with five functional areas as a basis for organisational
grouping as shown in Table 5.1 below. Traffic management also involves the Police and
Security Departments.
Table 5.1: The Role of Traffic Management in Urban Transport Administration
Urban Transport
Administration
Planning
Sub-Functions
Traffic Management (TM)
Land use planning

Transport network and
service planning
Management of roads and
road use
Public transport
development and
management





Good land use planning is a pre-requisite
for successful traffic management.
TM policy and strategy developed
within context of Transport Master Plan.
Functional road hierarchy is a prerequisite for successful TM.
TM policy and strategy developed
within context of Transport Master Plan.
TM planning, design & implementation.
TM operations and enforcement.
TM planning, design & implementation.
TM operations and enforcement.
Traffic Police

TM operations and enforcement.
Transport infrastructure

(road & rail) development
planning and programming 
Transport System
Management
Police & Security
5.5
The scope of a dedicated transport department usually embraces all functions except land use
planning and traffic enforcement. Transport agencies can be structured on a functional basis or
on a modal basis. A functional division separates planning functions from system management
whereas a modal separates planning and management of the road and traffic system from
planning and management of the public transport system
5.6
In some developing countries the structure is more complicated because traffic management is
divided between the Traffic Police (traffic control, traffic signs and lines, operations,
enforcement) and the municipal engineering and design agencies (physical works). And while
driver and vehicle licensing in most countries was originally vested in the police, it is now
recognised to be a civilian administrative function, with important revenue and policy
implications, rather than security function. Police purposes are usually served by on-line access
to licensing records to assist with traffic enforcement and crime detection. Parking management
is often not identified as a separate function in government. In future this will become an
important instrument of traffic policy.
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5.7
Most European cities developed before mass motorisation and were originally based on public
transport networks, often urban railway or tram networks. Their streets are unable to
accommodate high vehicular flows and parking capacity is limited. Traffic management
planning, design and implementation are typically the responsibility of a special department of
Roads and Transport Authority with the Traffic Police being responsible for traffic operations
and enforcement.
5.8
In Asia, Singapore, Hong Kong and Japanese cities are most often cited as models of effective
transport management. Singapore has progressively consolidated its transport functions into a
Land Transport Authority, while the administration of transport in Japan and Hong Kong
remains under government departments.
5.9
Traffic law and regulations: The regulation of road users and their vehicles forms the
backbone of traffic management practice. Traffic law and the enforcement of traffic regulations
naturally play key roles in determining not only driver and rider behavior but also what is
feasible to implement in terms of physical and regulatory traffic management measures. For
example, demonstrating or experimenting with new ways of managing traffic may require a
change in the regulations or the way they are interpreted.
5.10
Traffic management guidelines: Guidelines and standards for urban roads and traffic are well
developed in most countries and various codes of practice are in use. However, in some places
they tend to focus on the physical aspects of road and junction design. One of the main
differences between Europe and Asia is that Asia's growth is much more rapid. In Europe there
was the opportunity to develop steadily and to learn, test and consolidate new ideas in a
methodical and systematic manner. The cases of Hong Kong, Singapore and Japanese cities are
also very relevant. Developing countries in Asia are increasing looking towards these cities for
examples of current good practice. For example, Hong Kong's high density urban areas, strong
public transport network and systematic traffic management based on UK practice, could make
it an appropriate model for many Chinese cities. Traffic management guidelines and standards
need to cover a wide range of topics and good examples are the Hong Kong Transport
Planning and Design Manual and the Hong Kong Planning Standards and Guidelines.
5.12
Traffic Impact Analyses: A particular deficiency in developing countries is the lack of any
methodologies or legal requirements for carrying out Traffic Impact Analyses (TIA) which
document the effect of new developments on traffic volumes and patterns and develop
solutions. For more on TIAs, see elective reading material.
6.
Traffic Management Strategies and Techniques
6.1
Strategic Objectives: Within overall transport policy objectives traffic management strategies
can be carried out to achieve some or all of the following strategic objectives to:




protect and improve the environment
improve road safety
improve access and mobility for passengers and goods
improve the capacity and efficiency of traffic flows on main routes
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6.2
Specific Objectives: More specific objectives could be to:






contribute to a reduction in the adverse impact of traffic on the city environment
enhance the urban environment for pedestrians, passengers and cyclists
reduce the incidence of road accidents and the number and severity of casualties
improve quality of public transport system and to slow the modal shift to private cars
make the best use of scarce resources and to defer capital expenditure to the time
when it is inevitable
make immediate improvements in travel conditions while longer term policies and
measures are determined and finance is sought
6.3
These objectives hold true for all cities throughout the world. Usually a balance has to be
achieved between these objectives and trade-offs made, but all of them can contribute to a better
standard of living for all and to successful economic growth.
6.4
Network traffic management strategies: In this context, the traffic management strategy
options are elements or sub-strategies which can be utilized within the framework of three broad
network strategies:



Priority to the environment
Priority to public transport
Priority to private motor vehicles
6.5
Within this framework several specific strategy options can be developed to reflect the current
issues of concern. These are given in the Table 6.1 below which shows, for each of the three
broad network strategies, the key traffic management strategy options. Many of the latter are
elements of more than one broad strategy.
6.6
Traffic management techniques: There are six types of traffic management techniques that can
be used to implement the strategies and they are detailed below in Table 6.2.:
A
PHYSICAL MEASURES: the principles of enforcement by good design and
'self-enforcing' measures
B
REGULATORY MEASURES: require compliance and enforcement
C
INFORMATIVE MEASURES: need to be clear and systematic and should avoid
information overload
D
CHARGING MEASURES: to regulate demands
E
OPERATIONAL MEASURES: ongoing enforcement, regular maintenance and
regular assessment of the effectiveness of measures
F
EDUCATIONAL MEASURES: have to be monitored and evaluated regularly to
ensure effectiveness
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Table 6.1: Traffic Management Strategies
CATEGORY
PROTECT AND IMPROVE
THE ENVIRONMENT
IMPROVE ROAD
SAFETY
PRIORITY TO THE ENVIRONMENT
Category A traffic management strategies
state general principles and set out to favor
particular modes and restrict others. For
vehicles, the aim is a change in the 'active'
ownership levels and, assuming the same trip
rate, a corresponding change in the number of
vehicles by mode in the network. In some
cases, a change in the trip rate may occur.
Category B options reflect specific traffic
management techniques for changing the
network: changing the function of roads by
upgrading or downgrading, segregation and
grade-separation of modes, control of
crossing movements, link and junction
improvements designed to increase capacity,
and reduce delay and the number of stops.
A1.1 favor pedestrians
A2.1 restrict motorcycles
A1.2 favor non-polluting NMT
IMPROVE ACCESS AND
MOBILITY FOR
PASSENGERS AND GOODS
PRIORITY TO PUBLIC
TRANSPORT
A3.1 favor buses
A3.2 restrict private cars and
motorcycles
A4.3 restrict bicycles
A1.4 manage goods vehicles
B1.5 create environmental areas
B1.6 pedestrianize commercial
and residential areas
B1.7 reduce vehicle emissions by
reducing number of stops
B2.2 segregate pedestrians
from motor vehicles
B3.3 give priority to buses in
the network
B2.3 segregate bicycle
from motor vehicles
B3.4 segregate bicycles from
buses
B2.4 control pedestrian and
bicycle crossing
movements
C1.8 minimize severance: make
pedestrian and bicycle routes as
direct as possible
C3.5 minimize detours for local
traffic
C3.6 provide access and
servicing facilities for goods
vehicles
C1.9 remove through traffic and
direct it onto the primary road
network
B4.4 segregate pedestrians
and bicycles from motor
vehicles
B4.5 grade-separate
pedestrians and bicycles
from motor vehicles
B4.6 increase link and
junction capacities
B2.5 calm fast moving and
intrusive traffic
Category D options relate to accident and
casualty reduction.
A4.2 restrict pedestrians
A1.3 restrict private cars
B1.8 traffic calm local residential
and commercial areas
Category C options are concerned with
traffic routings: for example, reducing
severance for pedestrians and bicycles,
minimizing detours for traffic requiring
access, directing local and through traffic
onto appropriate routes
IMPROVE TRAFFIC
FLOWS ON MAIN
ROUTES
PRIORITY TO PRIVATE
MOTOR VEHICLES
A4.1 favor private cars and
motorcycles
B4.7 reduce delays and
queues at junctions
C4.9 remove local traffic
and direct it onto the
secondary and access road
network
D2.6 improve data
collection and analysis
D2.7 improve accident
response times and
emergency procedures.
D2.8 reduce accidents
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Table 6.2: Traffic Management Techniques
PHYSICAL MEASURES
1: reallocate existing space by
channelisation, barriers, bollards, changes of
level, changes of surface texture and color
REGULATORY
MEASURES
1: allow movements
INFORMATIVE
MEASURES
1: warning signs & lines
2: direct movements
2: advisory signs & lines
3: ban movements
3: regulatory signs and
lines
CHARGING
MEASURES
1: tolls on routes,
tunnels and bridges
OPERATIONAL
MEASURES
1: control of people, bicycles
and vehicles by traffic police
and civilian traffic wardens
EDUCATIONAL
MEASURES
1: driver and rider
testing and
training
2: bus stop queue control
2: road user
education
2: parking charges
2: segregate modes by barriers, reserves,
channelisation and grade-separation
3: congestion charging
4: install traffic signals
3: alter road layout by channelisation
4: direction signing
5: implement speed limits
4: alter type of junction control
5: street nameplates
6: restrict traffic by mode
5: install Area Traffic Control (ATC) and
traffic signals
8: design one-way systems, contra-flows
and gyratories
9: control speed by change of level,
alignment, texture
10: use signing and lining
11: provide pedestrian and bicycle crossings
at-grade
12: build pedestrian and bicycle overbridges
and underpasses
5: driver and rider
licensing
3: boarding and alighting
procedures at bus stops
6: bus and public
transport information at
stops and interchanges
8: restrict traffic by time
period
7: amenity information
signing for pedestrians
6: regular on-site 'fine-tuning'
of measures
9: implement parking and
loading/unloading
restrictions
8: Information
Technology and in-car
information systems
7: regular maintenance
10: implement temporary
regulations during
construction or for special
events
9: variable message signs
(VMS) for lane control
11. CCTV monitoring and
surveillance
6: public transport
fares
3: road safety
campaigns
4: monitoring and
surveillance systems
7: restrict traffic by size or
weight
6: close/open existing roads
7: build missing links
4: vehicle and bicycle
licensing
5: regular assessment of the
effectiveness of measures
10: variable message
signs (VMS) for car
parks
12. red light violation
cameras
13: provide bus stop/taxi ranks
13. speed limit cameras
14: widen footways
15: provide landscaping and street furniture
16: temporary measures during new road
construction and urban development
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6.7
Key techniques: There are several key traffic management techniques that can be used to
implement the traffic management elements of any strategy and these are outlined below.
Area Traffic Control (ATC): ATC is usually used to describe a system with a substantial
number of traffic-signaled junctions in an urban area coordinated by a central computer. The
basis is the allocation of road space and road time in a coordinated manner to regulate vehicle
movements in sections of the road network. It is thus possible to derive widespread advantages
in terms of freer flowing traffic, reduced journey times, and reduced environmental pollution.
ATC systems can make the best use of existing network capacity and reduce journey times
without creating adverse environmental effects (indeed by reducing congestion and delay they
can help in reducing vehicle noise and pollution); and they can provide the basis for an
expanded control system incorporating such features as variable message signs, congestion
monitoring, and emergency vehicle priority. ATC can also be a catalyst for other traffic
management. In conjunction with other traffic management techniques, ATC can provide a
cost-effective and efficient means of implementing a range of flexible traffic management
strategies. In cities in developed countries, traffic signal coordination in city centers is
standard practice. In developing countries, the rapid increase in urban traffic congestion has
led to more and more cities seeking some form of ATC to complement new road infrastructure.
For more on ATC, see elective reading material.
Junction Channelisation: The capacity and efficiency of junctions can be increased by
chammelizing vehicles into direct paths through the junction, tightening up stoplines and
decreasing lost time to clear the junction. The safety of pedestrians can be enhanced by physical
islands and the need for less time for pedestrians to cross a tighter junction..
One-Way Systems: One-way systems and gyratories can increase the capacity for motor
vehicles, particularly where there are three-lane roads whereby all three lanes can be fully
utilized. Bicycles and buses can be catered for by contra-flow bus lanes. Parallel signalized
pedestrian crossing facilities can be included in signalized junction control with no loss of
capacity for traffic.
Public Transport (PT) Priority Measures: High quality road-based public transport services are
vital to achieve maximum effectiveness from the road network and to offer an acceptable
alternative to the non-essential use of private cars. Most urban transport is provided by buses but
PT systems also include guided buses, trams, light rail and metro. Traffic management measures
for PT priority include: comprehensive route-length bus priorities; 'park and ride' systems; withflow and contra-flow bus lanes; bus priority at traffic signals such as a 'bus-advance area' and
exemptions from banned turns; bus-only roads (exclusive busways); bus and pedestrian streets;
bus 'gates' which control the point of access to busways to ensure compliance by other vehicles;
bus boarders whereby the footway is extended out into the carriageway to improve boarding and
alighting. A common traffic engineering measure is the provision of bus bays but these do not
generally give priority to buses; rather they improve conditions for vehicles other than buses by
making buses stop off the main carriageway. For more on PT priority measures, see elective
reading material.
Traffic Calming: The term 'traffic calming' covers a range of techniques designed to reduce the
adverse effect of traffic in urban streets. Traffic calming is a means of controlling vehicle
speeds, reducing accident risks, minimizing severance of communities and improving the
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environment using self-enforcing traffic engineering measures such as road humps, chicanes and
carriageway narrowing to discourage non-local traffic. The advent of traffic calming has marked
a significant change in the approach to traffic engineering in developed countries. The traditional
approach was to design road layouts to accommodate increasing volumes of traffic and this led to
an open-road impression which, outside congested periods, allowed excessive speeds and has
contributed to the domination of urban road by motor vehicles. Traffic calming has allowed this
approach to be re-examined, leading to schemes which benefits all road-users including cyclists
and pedestrians. For more on Traffic Calming, see elective reading material.
Urban Road Safety Management: This is a structured approach to accident prevention and
casualty reduction whereby a strategy for each urban area allows national, regional and local
accident reduction targets to be reflected in specific safety objectives. Such initiatives are
related to wider policies for an area, balancing safety, traffic, environmental and land-use
objectives. The focus is on the development of road safety plans involving the clarification of
road functions, accident analysis and investigation, assessment of traffic flows and
performance, and the setting of safety objectives for each part of the road network. Typical
measures implemented would include physical traffic engineering measures, road user
education, training and publicity measures, and enforcement. For more on Urban Road Safety
Management, see elective reading material.
7.
Transport Demand Management (TDM) Strategies
7.1
The rationale for TDM: It is increasingly becoming accepted that unrestrained travel by
private car within cites cannot be accommodated. This is due to a combination of financial
constraints and concerns about the adverse impact of traffic on local communities and their
environment. Allowing traffic to grow to levels at which there is extensive and regular
congestion is economically inefficient. Congested conditions also aggravate the social and
environmental impacts of traffic by increasing noise and polluting emissions, delaying public
transport and service vehicles, and making conditions unpleasant for walking and cycling.
Congestion in cities encourages the relocation of activities, people and jobs out to the urban
fringe resulting in urban sprawl and a greater dependence on cars.
7.2
Economic efficiency: Historically, the main reason to manage demand focused on economic
efficiency. The economic rationale was that unless the price directly incurred by someone in
making a journey covered the full costs of the journey, their travel would impose a net cost on
the community. These full costs include the personal costs which the traveler incurs (vehicle
running costs, fuel, parking etc) and the social costs which the traveler imposes on the
community through adding to congestion, increasing the potential for accidents, generating
adverse environmental impacts and contributing to severance. As the marginal costs imposed
on others vary by location, time and traffic conditions, it is argued that the charges incurred by
vehicle-users should also vary.
7.3
Quality of life: However, the argument for managing demand has broadened beyond that of
economic efficiency. It reflects increasing concern about the impacts of congestion on the
quality of life in urban communities, particularly the effects of noise and air pollution, and
severance. Limitations on funds available for investment in urban transport has also
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contributed to the debate about the extent to which demand should be restrained to match the
supply which can be provided.
7.4
Sustainability: There is also a growing recognition of the need to achieve 'sustainability' – in
other words, to manage development and transport in such a way that 'meets the needs of today
without compromising the ability of future generations to meet their needs' (UN, Our Common
Future (The Bruntland Report), Report of the United Nations Committee on Environment and
Development, 1987. The World Bank has distinguished between 'economic and financial
sustainability' which requires the efficient use of resources and the proper maintenance of
assets, 'environmental and ecological sustainability', which requires that the external effects of
transport are fully taken into account in determining future development, and 'social
sustainability', which requires all sections of the community to benefit from improved
transport. (The World Bank, Sustainable Transport: Priorities for Policy Reform, The World
Bank, Washington DC, 1996.) Each of these is relevant to TDM.
7.5
Balance between new road building and TDM: Although the construction of additional road
capacity can alleviate some of the effects of congestion, the benefits may be counterbalanced
unless growth in traffic volumes can be restrained. This issue is particularly acute in
developing countries where the pace of motorization is rapid and road building programs are
given priority funding. Such countries have an opportunity to learn from the experience of
developed countries.
7.6
Strengthening the economy: Local and national governments place a strong emphasis on
strengthening the economy. In particular, local governments seek to ensure that their city is an
attractive place in which to live, work and do business. Cities and towns are not isolated and
competition is regional, national and international. While fears of competitive disadvantage
may hold back the adoption of TDM, it is also possible that TDM will stimulate a local
economy and prevent it from deteriorating.
8.
Transport Demand Management Techniques and Measures
8.1
Objectives of TDM: The objectives of TDM are to:
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8.2
reduce congestion and thus improve economic efficiency
improve the quality of life by improving the local environment
provide a stimulus for the local economy
reduce local and global impacts of traffic emissions
Need for a package of measures: Not all of the above objectives are complementary;
measures designed to satisfy one objective can be counter-productive with respect to others.
There can be significant differences between the short- and long-term effects of some
measures. Thus, a carefully designed package of measures which address a balance of
objectives will usually be needed. Any single TDM measure is unlikely to be adequate or
acceptable by itself. A successful policy would require a combination of measures where some
would act as 'sticks' and others as 'carrots'.
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8.3
Public acceptability and political risk: Despite concerns about the impacts of congestion, the
public is generally not willing to accept significant reductions in personal mobility resulting
from the implementation of TDM. This issue has to be overcome for TDM to be successful
and thus there is also a significant political risk for leaders and city mayors in implementing
such radical policies. TDM measures usually need to be severe in order to achieve substantial
changes in the use of private cars. However, consideration of what politicians are prepared to
put forward and what the public will accept, usually result in a gradually increasing set of TDM
measures allowing the public time to adapt. In the past, there were also privacy issues. For
example, Hong Kong's proposals to introduce electronic road pricing (ERP) in the 1980s were
shelved partly because the technology was not advanced and personal data was required to
charge road users. With current technology, the issue of privacy should now no longer be a
bar to implementing TDM.
8.4
One of the major challenges is to devise measures which do not unduly restrict personal
mobility and which do not put local economies at risk. TDM measures include:
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8.5
Congestion charging and road-tolling: Congestion charging refers to the particular
application of road pricing to manage demand in congested conditions. Since it can be argued
that congestion is the result of imperfect pricing, congestion charging would appear to be the
most rational means by which demand can be balanced with supply. Alternative charging
systems include:
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8.6
congestion charging and road-tolling
road-user charges levied on fuel
controls on vehicle use
controls on vehicle ownership
controls on land-use development
public transport improvements
encouraging more travel by foot and bicycle
encouraging greater use of telecommuting
intelligent transport systems (ITS)
parking controls and pricing
physical measures of traffic restraint
point-based charging linked to cordons, cells or screenlines
time-based charging in which charges are a direct function of the time spent
traveling within the charged area and time period
distance-based charging in which charges are a direct function of the distance
traveled within the charged area and time period
congestion metering in which the charge is based on the amount and degree of
congestion encountered during a journey; this is determined by the moving average
speed calculated over a preceding defined distance
Singapore: The first urban congestion charging system to be implemented was the Singapore
Area Licensing Scheme (ALS) which came into operation in 1975. In 1998 it was upgraded to
Electronic Road Pricing (ERP) whereby all vehicles wishing to enter the cordon between 0730
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– 1900 hours have to have an In Vehicle Unit (IVU) into which a smartcard is inserted. For
more on Singapore's experience of road pricing, see elective reading material
8.7
London: The London Congestion Charging Scheme was launched in February 2003. 800
cameras scan the number plates of the 250,000 cars that enter the city centre each day.
Between 0700 and 1830 hours, vehicles not specifically exempted will have to pay a one-off
charge of £5 per day. For more on London's experience of road pricing, see elective reading
material.
8.8
Road-user charges levied on fuel: The economic rational for congestion charging is that the
users of motor vehicles do not perceive the true costs of using their vehicle, either at the point
of use or at the time they make individual travel decisions. Thus there is a case for increasing
the generalized cost of car use closer to the point of use by increasing the price of fuel through
taxation. However this type of TDM is indiscriminate in its effect in that rural car owners may
have no real alternatives to using their cars for essential travel. Differential pricing is not
feasible since fuel bought in lower price zones can be used in those where prices are higher.
Furthermore it is likely that the impact would be only a reduction in optional leisure journeys
and the impact on urban congestion would be minimal. While fuel prices could be an element
of a national TDM policy, they are not an appropriate measure for local TDM where the
objective is to reduce motor vehicles in particular localities and times.
8.9
Controls on vehicle use: Demand can be managed by using regulations to control the use of
vehicles. In Bologna and other Italian cities, only essential users are issued with permits to
enter the historic city centre. The scheme also encompasses public transport improvements,
parking controls and pedestrianization. 'Odds and evens' schemes in which use of vehicles is
permitted on alternate days for vehicle registrations ending in odd and even numbers are
popular in many Chinese cities and have been implemented in Athens and Sao Paulo.
California has introduced ride-sharing schemes to reduce the volume of 'drive alone' commuter
journeys. One risk of 'odds and evens' schemes is that it encourages and increase in the
number of vehicles owned as households and businesses buy both odd- and even-numbered
vehicles. Also, effective and tight control, monitoring and enforcement are required to avoid
erosion of the scheme through fraud and evasion.
8.10
Controls on vehicle ownership: It is possible to contain growth in car-use by restraining
growth in vehicle ownership. This has been a key feature of Singapore's transport policy.
Initially Singapore exercised control on car ownership through high import duties and high
annual charges with a charge-structure designed to encourage the scrapping of older cars and to
discriminate against company car ownership. However, continued rapid growth of vehicle
ownership led in 1990 to the introduction of absolute limits on the number of vehicles which
could be registered. Hong Kong also has high duties and charges for owning a car.
Significantly, both Singapore and Hong Kong have no local vehicle manufacturing interests
and they are also city states in which the economy of rural areas is not an issue. In parts of
Japan, it is necessary to prove that a parking space is available before a car can be purchased.
This condition is also applied in Hong Kong, Beijing and other Chinese cities. Car Clubs,
through which access to a car is provided when required rather than by direct ownership
operate in Lucerne in Switzerland, Bremen in Germany and Edinburgh in the UK.
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8.11
Controls on land-use development: Since travel is a derived demand, it should be possible to
reduce demand overall through changes in land-use location policies. It could be argued that
much of the increase in the use of cars is a direct result of policies which have allowed the
dispersion of major activity centers to the fringes of urban areas. Many of these locations are
often not easily accessible by public transport. Development control is only viable as a TDM
in the medium to long term and will have to complement the need for economic development.
8.12
Public transport improvements: Investments in public transport so that it becomes an
attractive alternative to the car focus on providing a high quality service that is affordable,
convenient, reliable, fast and safe. The heart of such investments usually focuses on buses but
metro and light rail also play a large part. Measures include: comprehensive route-length bus
priorities; with- and contra-flow bus lanes; bus priority using traffic signals; bus-only roads;
high capacity busway transit, metro and light rail; and 'park and ride' combining driving and
public transport
8.13
Encouraging more travel by foot and bicycle: Many urban journeys are short and well
suited to walking or cycling. To encourage greater use of these modes, better facilities which
meets the need of pedestrians and cyclists and which provide safe, direct and easy routes to
activity centers. Measures include: transport strategies to promote and provide for walking and
cycling; development of pedestrian and cycle networks; traffic calming; dropped curbs at
pedestrian crossings; pedestrian refuges; at-grade pedestrian crossings; footbridges and
subways; pedestrianized areas; cycle lanes and cycle tracks; cycle parking; and 'bike and ride'
combining cycling and public transport,
8.14
Telecommuting: The information revolution is heralding fundamental changes in the way
people work and where they work, transforming the relationship between work and home
locations, and the need for travel. By working from home or form local telecommuting centers,
travel to and from work has the potential to be reduced.
8.15
Intelligent transport systems (ITS): The development of advanced transport telematics and
the use of intelligent transport systems (ITS) is expected to contribute to increasing efficiency
in travel, not least through the provision of real-time information. Road users should
increasingly be able to plan their journeys to avoid congested areas and times. Smartcard based
payment system could contribute towards the creation of the seamless journey in which a
traveler may use different systems, provided by different operators with all fares and charges
paid by the use of a common smartcard. ITS measures include:
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variable message signs (VMS)
route guidance through in-vehicle information systems and navigation systems
journey planning using electronic pre-trip information systems
real-time public transport information displays systems
area traffic control (ATC)
vehicle location systems using global satellite positioning (GPS) and geographic
information systems (GIS)
ramp metering and access control for expressways
automatic incident detection and management
CCTV surveillance and monitoring
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weather monitoring and response
image processing systems
automatic payment systems using smartcards
8.16
Parking controls and pricing: While parking controls including pricing can be used to
influence vehicle ownership, their primary use as a TDM measure is to regulate parking
capacity and to allocate the available space between different groups of use. However, the
control of parking affects only trips with a destination within the area subject to the controls,
Used by itself parking control can reduce congestion for those vehicles passing through the
controlled area, with the result that through traffic flows can increase. The use of parking
controls as a TDM measures is weakened by the fact that in most urban areas, a high proportion
of parking spaces are in private non-residential (PNR) car parks owned by business and are not
under public local authority control. Much of PNR stock of parking spaces is used for
employees; parking, normally free of charge. It could be argued that anyone with a free and
guaranteed parking space provided at work does not bear the full costs of their journey to work.
As a result, they may make transport modal choices and residential location choices which are
economically inefficient in a community context. For more on parking, see elective reading.
8.17
Physical measures of traffic restraint: Traffic can be managed through the use of physical
measures designed to make the use of private motor vehicles less attractive. However, physical
measures are unlikely to reduce demand on their own and they need to be coupled with other
measures. Physical measures are likely to focus on :
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traffic management measures such as speed limits, area traffic control (ATC) and
traffic signals, reallocation of existing space by channelisation, barriers, bollards,
changes of level, changes of surface texture and color
traffic calming whereby speed is reduced and travel distances extended
public transport priority measures whereby road space is allocated to public
transport and high occupancy vehicles (HOV) to deter short distance travel by car
parking controls whereby private parking is strictly controlled and public parking
controls aim for an efficient use of the space available
8.18
For example, York in the UK has a policy of reducing the use of motor vehicles through a
combination of physical and regulatory measures and by encouraging bicycles. Gothenburg in
Sweden has sought to reduce traffic in its city centre by creating a system of cells between
which there is no direct access for cars; in order to move between the cells, drivers have to
return to a ring road which encircles the whole area.
8.19
The role of traffic management in implementing TDM: Traffic management (TM) measures
play a key role in implementing Transport Demand Management (TDM) strategies but they
should not be confused with TDM. TM describes a set of techniques and measures used to
implement a transport strategy in conjunction with other measures such as new road
infrastructure, planning and environmental measures. TDM is a strategy that may in the main be
implemented by traffic management techniques but may also require techniques outwith the
scope of traffic management such as fiscal and planning measures.
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9.
Elective Reading List
9.1
9.2
9.3
9.4
9.5
9.6
9.7
9.8
Traffic Impact Analysis (TIA) Methodology
Area Traffic Control (ATC)
Public Transport Priority
Traffic Calming
Urban Road Safety Management
Singapore Electronic Road Pricing (ERP)
London Congestion Charge
Parking
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