Driver views on speed and enforcement

This paper reports on the results of a drivers' survey regarding the effects of speed cameras for speed enforcement in Israel. The survey was part of a larger study that accompanied the introduction of digital speed cameras. Speed camera deployment started in 2011, and till the end of 2013 twenty-one cameras were deployed in interurban road sections. Yearly surveys were taken between 2010 and 2013 in 9 gas stations near speed camera installation sites in order to capture drivers' opinions about speed and enforcement. Overall, 1993 drivers were interviewed. In terms of admitted speed behavior, 38% of the drivers in 2010, 21% in 2011, 13% in 2012 and 11% in 2013 reported that their driving speed was above the perceived posted speed limit. The proportion of drivers indicating some speed camera influence on driving decreased over the years. In addition, the majority of drivers (61%) predicted positive impact of speed cameras on safety. This result did not change significantly over the years. The main stated explanation for speed limit violations was time pressure, while the main stated explanation for respecting the posted speed was enforcement, rather than safety concerns. Linear regression and sigmoidal models were applied to describe the linkage between the reported driving speed (dependent) and the perceived posted speed (independent). The sigmoidal model fitted the data better, especially at high levels of the perceived posted speeds. That is, although the perceived posted speed increased, at some point the actual driving speed levels off (asymptote) and did not increase. Moreover, we found that the upper asymptote of the sigmoidal model decreased over the years: from 113.22 (SE=18.84)km/h in 2010 to 88.92 (SE=1.55)km/h in 2013. A wide variance in perceived speed limits suggest that drivers may not know what the speed limits really are.