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Road Pricing Context













Decision Making



Implementation and Evaluation



Case Studies






Dutch National Case









The Hague


Urban Road User Charging Online Knowledge Base

What Is Involved In The Monitoring And Evaluation Process?

The monitoring plan involves three key stages:

  • Development of a monitoring plan
  • Specification of baseline indicators
  • Understanding underlying changes.

Development of a Monitoring Plan
A large proportion of the work required for evaluation is the collection of data. The procedures for this should be considered in the Business Model (Chapter 5) at the scheme development stage.
Evaluation should cover all the objectives listed in Table 2.1 (Chapter 2). In relation to these, Table 15 1 sets out the potential sources of information that could be used to monitor performance of the RUC scheme.

Table 151 Potential Sources of Information for Monitoring and Evaluation



Potential Sources of Information

Congestion relief

Traffic Flow, Speed and Delay Data


Traffic Flow Data/ Modelling

Revenue growth

Revenue Collected/ Enforcement Cost Data/

Penalties Issued

Economic growth

Business and Economic Impact Survey


Difficult to measure


Traffic Flow Data; Attitudinal Surveys


Accident Analysis Data

Equity/Social Inclusion

Social Impact Monitoring

Future Generations

Difficult to measure


At the same time, Table 15 1 also highlights areas where knowledge is lacking in attempting to develop robust, universally accepted indicators for monitoring. For example, there is little advice on how the future generations objective can be monitored and usually proxy measures such as environmental targets are used.

The Monitoring Plan also needs to define where and when the data are to be collected. The spatial coverage will be determined by the design of the scheme and its anticipated impacts. At the very least a distinction should be drawn between the charging zone, its boundary and the approach roads to the boundary. Temporal coverage during the day will also depend on scheme design; it may be appropriate to distinguish between peaks and off-peak within the charging period as well as the periods immediately before and after changes operate. Timing over the longer term should focus on regular surveys at the same time of the year, to avoid extraneous effects. In addition some short term surveys will be needed immediately after implementation to ensure that immediate impacts are acceptable. London and Stockholm have provided more detailed monthly data, which dealt with both the short term and seasonal trend needs.

Specification of Baseline Indicators

It is important to determine what the base conditions are against which the indicators in Table 2.1 are to be compared. All data need to be recorded for a period without URUC in place, and also without any of the preparatory traffic management measures or complementary policies. Such data needs to be objective, and not to exaggerate the extent of the problems which URUC was designed to overcome. For example, there were suggestions in London that congestion had been aggravated by traffic signal changes prior to implementation which accentuated the effects of the scheme. While unfounded, these criticisms were difficult to refute. Once again, monthly trend data, starting several months before implementation, as obtained in London and Stockholm, will help overcome this problem.

Understanding Underlying Changes

For the reasons mentioned in Chapter 6, it is clear that road user charging can lead to significant changes in travel behaviour. This could include rerouting of trips to avoid the charges, seeking alternative destinations for certain trips, changing the timing of the trips, changing mode and even abandoning the trip altogether.
Regular monitoring of traffic flow changes (in both private and public transport) as well as the use of “soft modes” is a key part of the evaluation process. However, traffic flow data will not be able to provide information on some of these changes or more generally, on why the behaviour has changed. Hence further analysis through the use of panel surveys (a panel is a group studied on repeated occasions) and surveys of businesses are very important.

Evaluation Methodology

Once the data have been obtained from the monitoring process for a sufficient period (typically at least a year after implementation), it will be possible to incorporate them into a formal evaluation of the scheme. The evaluation methodology can be developed using any of the approaches described for appraisal in Section 11.3.2. It is clearly appropriate for the evaluation to be conducted using any standard conventions for appraisal and evaluation in that city or country, such as agreed values for attributes such as time and accidents, for discounting and for any weighting of other objectives. However, as noted in Section 15.1, evaluation can also be used by other cities to decide whether the performance achieved merits consideration of URUC in their cities. For this purpose, each city should be able to apply its own values and weights. Thus the raw data for the evaluation should ideally be retained for analysis as well.

No information on this theme is currently available from the case studies