Assessment of Peripheral Pavement-Marking Effectiveness on Traffic Calming by t Test (Case Study: Izadshahr Gateway)

Speed management is an important factor to keep road sections safe, especially at gateway of cities created along the main roads. Perceptual traffic calming is one of the methods to control and reduce the speed of vehicles. Peripheral transverse marking with decreasing intervals was one of the specific perceptual traffic calming method which was implemented in Izadshahr gateway. Effectiveness of the marking on speed reduction was assessed with comparing the mean speeds of vehicles before and after marking implementation by t-test at 95% confidence level. The vehicles’ speed was recorded by radar instrument once before marking implemention as before study and twice after marking implemention as early-after and long-after studies. Speeds were categorized in three general modes of all vehicles, with respect to vehicle classification (light or heavy) and with respect to time (day or night). Results showed that the greatest reduction in vehicles’ mean speed was 5.49 km/h at night mode of early-after study in comparison to before study. Generally, there was decreasing effect of marking in long-after study. But it got reduced with respect to the early-after study.