This chapter assesses the use of cost–benefit analysis for evaluating transportation schemes which fall into two categories. The first category comprises infrastructure investments designed to improve inter-urban and intra-urban and regional transport links in terms of speed, safety and convenience. The second category comprises projects of traffic control in cities, examples of which include traffic law enforcement and restraint on automobile use in city centres. For traffic control projects which reduce congestion and delay in the control area – sometimes at the expense of increased travel time, cost and inconvenience to some groups of travellers – many of the items occur. Estimation of the value of working time has been regarded as relatively straightforward. The conventional approach is to measure it in terms of average gross earnings for the type of working time saved, with an additional sum for extra costs associated with the employment of labour.