Abstract
This paper is a rejoinder to a commentary on "Supply Curves for Urban Road Networks." It raises six issues on which there remain differences in understanding: 1) what units to use to measure demand, 2) the rate of demand, 3) the units with which supplied travel is measured, 4) the precise definition of throughput, 5) the units with which to measure cost and 6) supplied time per kilometre. Temporal dependency of the elements of travel demand and costs extend to whether the network was congested or free-flowing in the period immediately before a trip, which could be among the most problematic effects to estimate. (A)