Traffic flow parameters development modelling at traffic calming measures located on arterial roads

Abstract

Controlling the speed of vehicles is essential in some parts of the roadway. One way of controlling speed is to use static control devices i.e. traffic calming measures, which reduce the speeds of vehicles and thereby increase safety, while produce discomfort when crossing over it. In this study, three types of traffic calming measures located in Mosul city are investigated: flat-topped hump, single bump, and double bump. A data related to the driver’s behaviour, such as driving speed at different locations from the device, vehicle headways, travel times, and delays are obtained. The data are collected using video camera and speed radar gun instruments. Thirteen traffic calming measure locations on arterial roads were selected. The speed reduction at calming devices are 71.6%, 66%, and 60% for flat-topped humps, double bumps, and single bumps respectively. The acceleration value ranges from 0.424 to 1.107 m/sec2, while for deceleration from 0.039 to 1.042 m/sec2. The highest acceleration and deceleration values are at flat-topped hump and double bump respectively. The arrival rates of the traffic platoons before calming location follows the Poisson Distribution for both single and double bumps, while in the case of flat-topped humps the Binomial Distribution shows to be the best one followed. Departure rate headways after crossing follows a continuous Exponential Distribution. Rate distributions are validated by Chi-square and Kolmogorov-Smirnov non-parametric statistical tests for final validation, and models are correlated with high coefficient of determination values. Acceleration noise as a powerful speed change measuring parameter is selected to be measured along the test sections was studied and found that the higher value is for flat-topped hump. The highest delays from travel time measured on both up and downstream locations are for the double speed bump.