Unfortunately, as a result of the restrictions arising from the CoviD-19 pandemic, it is not currently possible to update the KonSULT website. It is being maintained as a teaching resource and for practitioners wishing to use its Measure and Package Option Generators and its Policy Guidebook. Practitioners wishing to use it, should do so on the clear understanding that recent experience on existing and new policy measures has not been incorporated.

Decision Makers' Guidebook

Policy instruments

What do we mean by policy instruments?


Types of policy instrument

  • Land use measures
  • Infrastructure provision
  • Infrastructure management
  • Information provision
  • Attitudinal measures
  • Pricing

Policy instruments are the tools which can be used to overcome problems and achieve objectives. They include conventional transport methods such as new infrastructure, traffic management and pricing policies, but increasingly they also involve attitudinal changes and use of information technology. Equally importantly, land use changes can contribute significantly to the reduction of transport problems. Policy instruments can be implemented throughout a city (for example a fares policy), or in a particular area (e.g. a light rail line), or at a particular time of day (e.g. a parking restriction). In many cases they can be implemented at different levels of intensity (e.g. for fares or for service levels). Rarely will any one policy instrument on its own tackle all of a city’s problems, or meet all of its objectives. It is important, therefore, to develop strategies which involve a combination of policy instruments; we look at this further in Section 11.

What is the range of policy instruments?

We have identified over 60 types of policy instrument. There are several ways in which they can be categorised; we have chosen to do so by type of intervention: land use measures; infrastructure provision; management of the infrastructure; information provision; attitudinal and behavioural measures; and pricing. We have then, as appropriate, considered separately those which influence car use; public transport use; walking and cycling; and freight. Experience with each of these policy instruments is described more fully in a project report and many are already included in our interactive Policy Guidebook. The full range of instruments is shown in the list below:

How should cities choose policy instruments?

how should cities choose?It is often very difficult to determine how a city has chosen the policy instruments which it decides to use. Often, as with road schemes, they are proposals with a long history, which are reconsidered every time a new strategy is developed. There are usually good reasons why they have never been implemented. It is much harder, but much more valuable, to start with a clean sheet, consider the full range of policy instruments, and decide which are likely to contribute most. There are two good reasons for this. Traditional solutions often have weaknesses which can be overcome by combining them with other instruments; this is a key principle of strategy formulation, as outlined in Section 11. Some of the newer policy instruments, like awareness campaigns and real time information, may well offer a significant contribution. For both these reasons, it is far better to start with the question: “Which of this list of policy instruments should I consider?” rather than simply: “How best can I make use of earlier proposals?”

How can problem-oriented planning help?

61The list of problems is the most useful starting point for this, but context will also be important. We have designed our Policy Guidebook, KonSULT, to enable users to seek a shortlist of instruments which are likely to be of most interest in their circumstances. We are also investigating new techniques for option generation which will be added to KonSULT as they become available. Experience in other successful cities is also useful; our case studies in Section 16 help with this. This is also an area in which participation can be valuable. Users, providers and other stakeholders may well have ideas which would otherwise be overlooked. Once a first set of possible instruments has been identified, they can be tested using the approach described in Sections 12 and 13. Our optimisation procedures, outlined in Section 14, offer a more rapid way of selecting the best combination of policy instruments from a longer initial list.

Why is it difficult to assess which policy instruments will be best?

62Unfortunately the evidence which is available on the performance of many of these policy instruments is very incomplete. In some cases this is because the policy instruments are novel, and experience is still limited; this is true, for example, for car clubs. In others we have simply failed to collect the evidence on what impact key policy instruments have had. This is particularly true of road building; the realisation, too late, that new roads could generate new traffic is one reason for policy on road building in some countries changing so abruptly. It is important, therefore, that all of us take the opportunity, when we implement significant changes, to measure and evaluate their impacts, and make that information available to others. This is particularly true of policies which have been less successful than planned; even though we may want to keep such experiences to ourselves, we can help others avoid making the same mistakes. We consider this further in Section 15.

64Even where experience is available it may not be directly relevant in another context. Light rail will work better in larger cities than in smaller ones. Walking and cycling provision are more important in high density areas than in lower density ones. Parking controls are likely to be more effective in city centres than elsewhere. Regulatory controls will be more acceptable in some cultures than in others. For all of these reasons it can be difficult to judge how transferable experience with successful policy instruments will be. This is a further reason for encouraging as much experience as possible to be recorded.

What information is available?

what info is available?Some projects have provided valuable information on certain types of policy instrument. VeloInfo provides a website on ways of selecting measures to support cycling; ARTISTS provides guidance on the redesign of street space; City Freight offers advice on the selection of measures to support, and control, the movement of freight. However, these sources are not comprehensive, and there is still limited guidance on many types of policy intervention.

We have attempted to overcome these limitations on information on policy instruments by producing a report which summarises the literature and by developing our web-based Policy Guidebook, KonSULT. The report, which was published in 2001, reviews the literature on all 60 policy instruments. KonSULT, which is designed to be more readily kept up to date, currently includes fuller information on 40 of them, and is being expanded to provide full coverage. For each policy instrument, it defines the instrument and describes briefly how it works. It then provides an assessment from first principles of its likely impact on each of the policy objectives and problems highlighted in Sections 7 and 8. This is followed by a series of case studies and a summary of the contexts in which the instrument is likely to be most effective.

The user is able to select possible policy instruments for further consideration from a list based on the categories identified earlier in this section; by a keyword search; or using a novel filter mechanism which allows the user to specify the type of organisation they represent, the type of urban area they are interested in, their principal objectives, the main problems which they face, and the types of strategy which they are pursuing. The last of these is based on the key strategy elements highlighted in Section 11. The final element in the coverage of each instrument is an assessment of the types of policy instrument which could complement it, either in reinforcing its impact or in overcoming barriers to its implementation. The treatment of barriers follows that outlined in Section 10. A further development will provide fuller guidance on the design of integrated strategies, and the potential for synergy between policy instruments.

How can performance be assessed?

performance assessedAll of these policy instruments will affect the performance of the transport system in one or more of three ways:

• By changing the demand for travel
• By changing the supply of transport facilities
• By changing the cost of provision and operation of the transport system.

Initial responses (e.g. changes in mode) may lead to secondary ones (e.g. increases in overcrowding). Each of these types of change will in turn affect performance against the objectives in Section 7. It is this first principles assessment of the likely impact of a policy instrument which helps to assess its potential contribution, and KonSULT is structured on this basis.

Changes in demand
When faced with a new policy instrument, or with a change in an existing one, such as a fare increase, the individual traveller has a number of options as shown in the box.

The scale of response will depend on the circumstances. Those who are directly exposed to a change will respond more strongly than those for whom the impact is indirect. Those who have fewer alternatives will be more reluctant to change. Longer term responses may well be stronger, as people have more time to respond, but the more dramatic responses such as changing work or home will depend on how permanent the change in policy appears to be. There is a substantial literature on such responses, typically measured by elasticities of demand.

Possible user responses

  • Continue as before
  • Change the number of journeys made
  • Combine journeys
  • Change destination
  • Change departure time
  • Change mode (including mixing modes)
  • Change route
  • Change ownership of vehicles
  • Change home

The level of change in demand can be determined by knowledge of the change in the policy instrument in question and of the relevant elasticity of demand. Demand elasticities are generally calculated by estimating the proportionate change in demand for a good or service resulting from a one percent change in a measure of the supply of that good or service. Demand can be measured in trips or in trip-km for a given mode in a given circumstance. Supply can be defined in a number of different ways, including price, travel time, frequency or overall (“generalised”) travel cost and it is important, in interpreting elasticities, to know which definition is being used. In particular, price might relate to “generalised cost”, whereby all monetary and time-related costs to the user are bundled together, assigning a value to the time elements, or it might be defined in relation to one particular component of cost, e.g. fuel price or parking cost. Elasticities can also be measured for demand for the mode being affected (for example bus trips in response to changes in bus fares) or for demand for a competing mode (for example car trips in response to bus fares). The latter is referred to as a cross-elasticity.

Changes in supply
Changes in the supply of transport can take a number of forms as shown in the box, some of which will have a direct influence on travellers, while others will only affect them if they are perceived.

For most policy instruments, it will be clear how they affect supply, but the scale of their impact may be difficult to assess.

Possible supply changes

  • Changes in the capacity of the road or public transport network
  • Changes in the allocation of road capacity
  • Changes in permitted speeds
  • Changes in the access cost or time to public transport
  • Changes in the costs of use
  • Changes in the information available

Interaction of demand and supply
The effects of demand and supply changes can best be interpreted by an understanding of the shape of demand and supply curves. A demand curve (see below) represents the way in which demand (in say trips) on the x-axis changes as costs (on the y-axis) rise or fall. A supply curve shows how costs of use, on the y-axis, rise as the level of use, on the x-axis, rises. That shown is a typical supply curve in a road network, in which average costs rise slowly at first, as increased traffic results in reductions in speed, and then rise much more rapidly as capacity is reached and delays occur. A public transport supply curve would reflect, instead, the extra costs of having to wait for the next bus as bus capacity is reached. The intersection of the demand and supply curve determines both the number of users (X in the figure below) and the cost per user (Y in the figure below). These in turn can be used to determine the impact on both policy objectives and problems.


The way in which a policy instrument affects demand and supply curves will vary, as illustrated in the figures below, which represent five different types of change in the demand and supply for car use. In the first figure, the capacity of the road system has been increased, for example through traffic management; the supply curve has changed, but the demand curve, at least in the short term, has not, since the same number of users would wish to travel at a given cost. As a result, the number of users has increased, and the average cost of use has fallen. In the second figure, the capacity has been reduced, perhaps through a road closure; again the supply curve has changed, but the demand curve has not; the number of users has fallen, and the average cost increased. In the third figure, the demand for car use has fallen, perhaps through a reduction in public transport fares or a successful awareness campaign; the demand curve has changed, but the supply curve has not, since the costs of use at a given flow remain the same. As a result, the number travelling has fallen, as has the average cost of travel. In the fourth figure, the demand for car use has risen, perhaps through a deterioration in public transport services or an improvement in driver information. Again, the demand curve has changed but the supply curve has not; the number of car users has increased, as has the average cost of travel (though in this case, improved information may have reduced the perceived cost of use). In the fifth figure one of the many possible combinations of the above effects is shown. In this case, demand for car use has fallen, as has the capacity for car use. This could result, for example, from reallocation of road space to light rail. As a result both the demand and supply curves have changed. The number of car users has fallen, but the effect on average cost will depend on the relative changes in the demand and supply curves.

The principal types of cost change are:

  • Changes in capital costs, usually through the costs of new measures
  • Changes in the cost of vehicle operation for users, which are included in the supply costs above
  • Changes in the operation costs for suppliers, including enforcement, administration, and public transport vehicle and driver costs
  • Changes in the cost of maintaining and replacing the transport infrastructure and services

Changes in costs
The principal types of costs are capital costs of new infrastructure, operating and administration costs, and costs of maintenance and replacement. These will be offset for some instruments by income from users and from taxes. Changes in these costs and revenues are crucial in determining whether an individual policy instrument, or the overall strategy, is affordable. It is often the case that low cost instruments will offer greater value for money than major infrastructure projects. The main types of change in cost are shown in the box.

Causal chain diagrams are particularly helpful in understanding the interaction of these processes.

How does the Policy Guidebook work?

The coverage of each policy instrument in the Policy Instruments Guidebook is structured into five sections:

  1. A description of the policy instrument and the way in which it operates, with more detail provided for those which are less well known or more complex
  2. A first principles assessment, which assesses in turn the expected impacts on demand, supply and costs; considers the resulting implications for objectives and problems and indicators, both assessed on a -5 to +5 scale, with brief explanatory text; identifies the main winners and losers, again assessed on a -5 to +5 scale; and finally considers the severity of the main barriers to implementation, on a 0-5 scale, drawing on the general consideration of barriers in Section 6 below
  3. Presentation of the evidence from both case studies and desk studies, following a similar structure to that of the first principles assessment
  4. A summary assessment, which considers again the performance against objectives and problems, based on the evidence available (again on a -5 to +5 scale); assesses the likely contribution of the instrument in a number of contexts ranging from city centres, to higher and lower density suburbs, to smaller towns, again on a 0-5 scale; and briefly discusses potential side effects; and
  5. Identification of the complementary measures which are most capable of overcoming adverse side effects and reinforcing the performance of the instrument, as a link both to the coverage of these complementary instruments.

Which policy instruments are likely to contribute most to particular objectives?

70Given the comments above, it is impossible to suggest a set of policy instruments which will meet the needs of all cities. So much depends on each city’s priority objectives, the scale of the problems to be overcome, the policy instruments which are already in place, the combination of new policy instruments, the context within which they might be implemented, and the barriers to be overcome in doing so. However, it is possible to give general guidance on the types of policy instrument which are likely to have the greatest impact on specific policy objectives in four different types of area: city centres; inner suburbs; outer areas; and smaller urban areas. The tables show the extent to which each of the six types of policy instrument is likely to contribute to each of the eight objectives listed in Section 7.

City centres

In city centres, there will often be less opportunity for rebuilding to reflect better land use patterns, and new development will usually focus on economic growth. New infrastructure will be difficult to provide. Better management of the road network and improved public transport services can reduce congestion, protect the environment, improve residential streets and reduce accidents; improved services will also help reduce inequalities. Information and attitudinal measures will have limited impacts. Pricing, particularly of road space, will produce the single largest improvement in efficiency, and may also help protect the environment.


Inner suburbs

There will often be more opportunity for rebuilding in inner suburbs, and a greater need to assist the economy in this way. Effective land use strategies can help reduce congestion and pollution, and in particular enhance liveability. Infrastructure in inner suburbs is often outmoded, and their denser development can benefit from new public transport infrastructure. Inner suburban streets are often less well managed, and improved traffic management, reallocation of road space and enhanced service levels can contribute substantially. Information and attitudinal measures may have a greater role to play in encouraging public transport use and avoiding congestion. Pricing of road space will be important to avoid congestion spreading from city centres.


Outer suburbs

Outer suburbs are growing fastest, and effective land use planning is essential here to avoid unnecessary travel and to encourage less use of cars. Lower densities reduce the benefits of dedicated infrastructure. Management measures can help to ensure that roads are used efficiently and safely, while protecting liveability; good public transport services can help avoid over-reliance on the car. Information can help in promoting efficient travel, but attitudinal measures may be more effective in encouraging alternatives to the car. Pricing will be less important, but still needs to send consistent signals to car and public transport users.


Smaller urban areas

Smaller urban areas are often a microcosm of the conditions found in cities. Land use planning will be important for the reasons given for outer suburbs above. Infrastructure provision will often be less important because of the smaller population base. Management measures will offer significant contributions; roads and public transport in smaller towns may be less well managed, giving considerable opportunities for greater efficiency, a better and safer environment and more equitable provision. Information and attitudinal measures are important for the reasons given for outer suburbs above. Pricing may be less important, though as congestion grows the need for a balance between car and public transport costs will become more important.


Where can I find out more?

VTPI (2005)
City Freight
Velo Info

References...Section 18