(e) Demand Elasticity with Respect to Travel Time Good with (1992) estimated that the elasticity of vehicle travel demand at urban roads with respect to travel time is -0.27 and -0.57 in the short and long run, respectively (the values for rural roads were -0.67 and -1.33, respectively ). The elasticities of demand with respect to auto travel times, by trip type and mode, are summarized in Table 3.5. These are long-term elasticities in areas of high vehicle ownership: over 0.45 vehicle person (TRACE, 1990)