THE SENSITIVITY OF CAR TRAVEL TO ECONOMIC AND WEATHER FACTORS

An analysis was undertaken on changes in car traffic using published data. Changes in the absolute levels of average weekday and Sunday car traffic for January, April, July and October were extracted and related to corresponding weather and economic factors. Then the changes from year to year in the difference between July and January car traffic levels in relation to these parameters were analysed. The results showed that weekday car travel is virtually insensitive to other than the most stringent or favourable economic circumstances. Conversely Sunday car travel showed variations of up to plus or minus 20% of the average traffic levels as a result of stringent or good economic circumstances and similar variations for good or poor weather compared with average weather. However, the level of July Sunday car travel has remained virtually static since 1973 despite a 15% increase in car-owning households. The paper will be of particular interest to civil engineers involved in urban transportation network management and engineers and planners concerned with outdoor recreation facilities. (Author/TRRL)