New geometric design consistency model based on operating speed profiles for road safety evaluation

Abstract

ElsevierCamacho Torregrosa, FJ.; Pérez Zuriaga, AM.; Campoy Ungria, JM.; García García, A. (2013). New geometric design consistency model based on operating speed profiles for road safety evaluation. Accident Analysis and Prevention. 61:33-42. doi:10.1016/j.aap.2012.10.001. 1 NEW GEOMETRIC DESIGN CONSISTENCY MODEL BASED ON OPERATING SPEED PROFILES FOR ROAD SAFETY EVALUATION ABSTRACTIn order to reduce road fatalities as maximum as possible, this paper presents a new methodology to evaluate road safety in both design and redesign stages of two-lane rural highways. This methodology is based on the evaluation of road geometric design consistency, determining one value which will be a surrogate measure of the safety level of a two-lane rural road segment. The consistency model presented in this paper is based on the consideration of continuous operating speed profiles. The models used for their construction have been obtained by using an innovative GPS-data collecting method, based on continuous operating speed profiles recorded from individual drivers. This new methodology allowed the researchers to observe the actual behavior of drivers and to develop more accurate operating speed models than those which are based on spot-speed data collection. That means a more accurate approximation to the real phenomenon, and thus a better consistency measurement. Operating speed profiles were built for 33 Spanish two-lane rural road segments, and several consistency measurements based on the global and local operating speed were checked. The final consistency model takes into account not only the global dispersion of the operating speed, but also some indexes that consider both local speed decelerations and speeds over posted speeds. For the development of the consistency model, the crash frequency for all sites was considered, obtaining a model directly related to safety. This allows estimating the number of crashes of a road segment by means of the calculation of its geometric design consistency. Consequently, the present consistency evaluation method becomes an innovative tool that can be used as a surrogate measure to estimate road safety of a road segment even before its construction.

Design and development of driving simulator scenarios for road validation studies

“…The cartographic files were obtained based on a LIDAR with a density of 5 m mesh size, which is proper for this project. The horizontal alignment was obtained according to the methodology proposed by Camacho-Torregrosa et al (2013). In addition, the vertical alignment was extracted from GPS data of the tests.…”

New Consistency Index Based on Inertial Operating Speed

“…Other studies, such as the one carried out by Polus and Mattar-Habib (10), Cafiso et al (11) and Camacho-Torregrosa et al (12), are based on continuous speed profiles. They studied the global speed variation along a road segment, as a function of several indexes, and determined a single consistency value for the whole road segment.…”

Development of Continuous Speed Profile Using GPS at Johor Federal Roads F0050

“…If these trends continue, road traffic accidents are will be predicted to be the third important to contributed to the global burden of disease and injury by 2020. Among ASEAN countries [1,2], Malaysia has the highest road fatality and more than 50% of the road accident fatalities involved motorcyclist that represent more than two thirds of road accident victims. About 300 000 accidents reported and 1% of it is fatal accidents in Malaysia for every year.…”

“…Most consistency concepts today deal with the variation of vehicles speed but less variation types (heterogeneous) on road section and this speed variation is affected mainly by horizontal alignment and vertical alignment of roads [2,6,7]. Design consistency is measured by estimating the speed variation along successive geometric elements and evaluation of the speed deviation from the average speed [8].…”