Value of time multipliers for walk time, wait time, service headway, displacement time, reliability and congested travel time: review and meta-analysis of worldwide evidence

This study provides the most comprehensive review and meta-analysis of time multipliers that are fundamental to transport planning and appraisal. The attributes covered are: walk time, wait time, access/egress time, connection time, out-of-vehicle time and service headway, which are largely characteristics of public transport trips; travel time in various degrees of congestion and parking search time, which are features of car travel; displacement time; and a range of variables related to travel time variability. The evidence assembled covers 2872 multipliers drawn from 606 studies across 52 countries over the years 1963 to 2023. It was found that many of the multipliers vary between Revealed and Stated Preference data, with the former almost always larger, and over time, indicating a reduction where an effect was discerned. Other influences were detected from mode used, journey purpose and distance. The estimated meta-model implies credible multipliers across a range of illustrative scenarios. It can be used to deliver multipliers for use in planning and appraisal where none exist or to benchmark existing or emerging evidence. When compared with official recommendations, the meta-model’s implied multipliers challenge the long-established multipliers of two for walk and wait time, supporting a reduction to 1.75 or 1.50 depending upon the emphasis placed on Revealed or Stated Preference data. The results support official headway and late time multiplier recommendations but suggest refinements for the reliability ratio and congested time multipliers along with new guidance for displacement time multipliers.