Question to the Department for Transport:

To ask His Majesty's Government, further to the Written Answer by Lord Hendy of Richmond Hill on 10 November (HL11340), in the Transport Analysis Guidance what, if anything, is the smallest period of time that can be taken into account in evaluating time saved by a scheme under consideration.

Transport models are capable of capturing almost any scale of changes in journey time, down to fractions of seconds. Typically, these are aggregated across travellers to provide a measure of the impact of the scheme.

In the Department’s Appraisal Summary Table, used to capture the key results in the appraisal, promoters are requested to provide a breakdown of the total monetary value of net journey time changes by the following increments:

• Changes of 0 to 2 minutes
• Changes of 2 to 5 minutes
• Changes of greater than 5 minutes.