3.5 - Do minimum
- 3.1- Overview
- 3.2 - Method of evaluation
- 3.3 - Scope of analysis
- 3.4 - Stages of analysis
- 3.5 - Do minimum
- 3.6 - Travel impacts
- 3.7 - Costs of TDM programmes
- 3.8 - Benefits of TDM programmes
- 3.9 - Period of analysis
- 3.10 - Cost benefit evaluation
- 3.11 - Alternatives and options
- 3.12 - Sensitivity analysis
- 3.13 - Monitoring
- 3.14 - Selecting the appropriate evaluation method
- 3.15 - References
3.5 - Do minimum
Introduction
TDM evaluation is based on incremental impacts compared with a do minimum case. The do minimum is an assessment of the likely conditions that would exist at a given point in time in the absence of the proposed TDM programme including, for example, likely traffic for each mode, social and economic conditions. This is equivalent to the do minimum described in section 2 of
volume 1.
It is important that the do minimum is fully described in any analysis.
Examples
When evaluating an HOV lane, the do minimum could either be no additional lane, or an additional general-use lane. Similarly, when evaluating road pricing, the do minimum could be the same road capacity provided with a different funding source, less road capacity, or something in between.
Exceptions
For projects involving no pricing or infrastructure changes, eg travel behaviour change (TBhC) projects, or only small infrastructure changes, eg walking and cycling projects, there is no need to investigate/assess the benefits and costs of a do minimum. For these types of project only the incremental costs and benefits of the project need to be evaluated.
Note: For TBhC projects it is still necessary to have some information on the current and future conditions without the TBhC package as a basis for estimating the numbers of people changing their travel behaviour.
