Operating speed models for two-lane rural roads in Pakistan

Abstract

One of the suitable techniques used to improve safety on roads is to check the consistency of geometric design. The concept of design consistency has emerged worldwide, but no research has been found to date on design consistency in Pakistan. The most common parameter for the evaluation of design consistency is operating speed. Several models have been developed to predict operating speed on two-lane rural roads. However, these models were based on spot speed data collected through traditional speed measuring devices. This study uses continuous speed profile data collected using a vehicle equipped with a VBox (a global positioning system based device). Eleven test sections were selected in two provinces of Pakistan (i.e., Sindh and Balochistan). Driver behavior is also studied in the present research. Models were developed for prediction of operating speed on horizontal curves and on tangents. Validation of the developed models shows compatibility with the experimental data; hence, the developed speed prediction models can be used to evaluate the geometric design consistency of two-lane rural roads in Pakistan.