Original 1974 Abstract:

Different measures have  been proposed to restraint the traffic in towns to give pleasant environmental conditions, and to allow traffic to move at a reasonable rate. These measures include parking controls, road pricing, supplementary licences, physical barriers, and cordons of toll points round congested areas. The theoretical techniques required to analyse these policy proposals in a transport planning context have now been developed together with environmental impact appraisal methods, and a full study of the effects and the limitations of these different forms of traffic restraint has been carried out on two scenarios based on those designed by the City of Coventry for their Transportation Study. The situation in 1967, when a low level of parking control was quite sufficient to meet the practical and economic objectives, has been studied to show how the different restraint policies might be best analysed in lightly congested conditions. The 1981 forecast situation under the low investment option considered in the Coventry Study was then modelled to determine the effects and the economic results of different restraint schemes under the difficult conditions expected for that year. Traffic benefits are not the only positive results of restraint, and a special environmental impact assessment model has been developed and applied to show how the noise,_ smoke, lead, carbon monoxide, nitrogen oxides, and airborne hydrocarbon concentrations would affect people under each restraint option. It is clear that although the design of restraint systems can reasonably be undertaken, and the traffic and high levels of environmental impacts forecast, the evaluation of environmental factors to similar standards cannot at present be achieved. The distributional impacts, which could have wider social consequences, are also presented to show how different restraint instruments can have divergent distributional results even when the overall benefits reach the same aggregate totals. The scenarios used were not specifically tailored to the actual condition, present or expected, in the City of Coventry, and would have required considerable variations to achieve this. Comparative runs with other such scenarios did not, however, substantially alter the nature of the relative results discussed.