Ideally, the design and economic assessment of new road schemes would take due account of any behavioural responses to those schemes. However, few, if any, systematic attempts to monitor responses have produced incontrovertible evidence of their nature and timing. A major programme of work is therefore under way to assess the ways in which road users respond to changes in infrastructure provision in terms of trip re-routing, trip retiming, changes in mode-split, changes in trip distribution or changes in trip frequency (including entirely new trips). This paper reports on one route being studied as part of the programme, the final section in the creation of a new high-standard route, the A14 from the M1 to the A1. This road was expected to have a marked effect on traffic flows. Roadside interviews were conducted on screenlines across the corridor in June 1994, just before opening, and again one year later. Comprehensive counts of traffic on all major roads in the area were also obtained for the same periods. The aim was to detect reassignment, which might take place over a wide area, to examine changing patterns of origins and destinations, by trip purpose, and to look for evidence of induced traffic in the east-west corridor centred on the new route. The methodology used, the results obtained and conclusions drawn are discussed in the paper.
Samenvatting