Published in March 2018, Department for Transport’s ‘Congestion Dependent Values of Time in Transport Modelling’ details the conclusions of a feasibility study into the incorporation of congestion multipliers in highways and other transport models. ‘Congestion multipliers’ are applied to car values of travel time (CVTT) in free flow conditions to derive congested CVTT. The ‘value of travel time’ can be defined as the price people are willing to pay to acquire an additional unit of time. For example, a congestion multiplier of 1 implies travel time in congestion is weighted equally to free flow travel time whereas a congestion multiplier of 2 implies travel time in congestion is weighted twice as highly as free flow travel time. In this sense, the lower the congestion multiplier, the more preferable the option is for road users.

The Report explores the practical and theoretical implications of using congestion multipliers in transport modelling and appraisal.