Research and analysis

Values of travel time savings: understanding the uncertainty around the non-work values

Advice on the statistical confidence and uncertainty from the non-work values of travel time plus the benefits of re-sampling and re-estimating these values.

Documents

Advice on statistical confidence of appraisal values of non-work time

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Details

The report identified 4 areas of statistical uncertainty in values of travel times of:

  1. parameter uncertainty arising from estimation of the logit model
  2. parameter uncertainty arising from estimation of the meta model
  3. uncertainty regarding the values of future income levels
  4. the weighting procedure adopted for the base figure which utilises national travel survey data

The findings from this study helped improve analysis practice in the March 2017 transport analysis guidance of regarding user and provider impacts.

Published 29 October 2013