Urban Road User Charging Online Knowledge Base
What Are The Implications For Other Themes?
There are the following implications for other themes:
• Objectives: The objectives of road pricing schemes will determine the outcome indicators that need to be predicted. The ability to represent impacts in faithful and informative ways is likely to be important in demonstrating the extent to which objectives can be met. On the other hand, the inability to predict impacts in some areas may act as a significant constraint on the pursuit of related objectives.
• Scheme design: Prediction has, potentially, an extremely important role to play in informing scheme design, through representation of the impacts of a range of alternative scenarios. Depending on design details, traffic flows may be reduced on some routes but increased on others.
• Technology: Predictive work that focuses on the performance of technology may help to show which options are feasible and may also assist with technological design details.
• Traffic effects: While predictive models are designed to estimate traffic effects, the actual effects of implemented schemes will provide an important input to the enhancement of predictive models.
• Environment: Prediction of environmental effects is increasingly possible, but is much more robust for estimating emissions than concentrations or exposure to those concentrations.
• Economy: Prediction of the wider economic impacts of road pricing is one of the most problematic / least well developed areas of research. In economic theory, road pricing is considered to improve efficiency in the travel market leading to benefits throughout the economy. In practical policy-making, concerns exist about whether real road pricing schemes will lead to positive or negative benefits for economic activity within charged areas and whether unilaterally implemented schemes may affect economic competition between localities.
• Equity: Prediction of distributional impacts of road pricing across the population is likely to be central in determining equity effects but is difficult because many models do not reflect different user groups This may also be expected to feed into consideration of mitigation measures within scheme design.
• Appraisal: As will be discussed in Chapter 11, information for appraisal is generally derived from predictive models. Hence these areas are inextricably linked.
• Acceptability: The acceptability of road pricing may be related to perceptions of its effectiveness and how its impacts are distributed across the population. Prior to implementation, prediction is likely to be the most reliable source of this information and may play a critical role in the political process. In particular, evidence about the robustness of predicted outcomes will affect the levels of trust that politicians and the public will be prepared to place in the policy-making processes.
• Transferability: The ability to predict the impacts of road pricing may sometimes be critically dependent on whether information can be transferred reliably between different situations. In particular, variations in approaches to prediction and appraisal between different locations may affect how transferable outputs from one road pricing study are to another.
• Implementation: Reliable prediction, particularly of the short term impacts of road pricing, is fundamental to successful implementation. Stakeholder involvement in the prediction process should help to reduce the risk of unexpected and unacceptable impacts during the implementation process.
• Evaluation: Prediction does not contribute directly to the evaluation process, except as a reference against which predicted effects can be compared. But thorough evaluation will help in our understanding of the performance of road pricing schemes, and hence in our ability to predict them.