Volume 07,Issue 01

Calibration of Highway Safety Manual’s Crash Prediction Model for Rural Two-Lane Two-Way Roads in a Developing Country: A Case Study

Authors

Mohamadreza Haghani, Reza Jalalkamali, Hamidreza Haghani

Abstract
Road safety has attracted much attention in the last decades owing to the high fatality rate of road crashes. The high speed of drivers on rural roads results in more severe crashes occurring on this type of roads. Therefore, the safety of rural roads was analyzed in this study. Roads with different topographic types were chosen for data collection in Kerman province, Iran. Roadway characteristics were collected from field surveys and documentations. Also, crash records of the studied roads were gathered for a three-year period. Then, the Highway Safety Manual’s (HSM) crash prediction model was calibrated for the study area. The performance of the HSM’ model was compared to the jurisdictional crash prediction model created in a previous research using the data from the same region. Also, the Empirical Bayes (EB) method was utilized to estimate expected crash frequencies. The calibration factor of 1.17 was calculated for the HSM’s crash prediction model using EB. The evaluation results showed that the jurisdictional model had higher precision and lower bias compared to the HSM’s model. However, utilizing EB, the performance of the HSM’s model became better than the jurisdictional model. At the end, this research verified the transferability of the HSM’s crash prediction model to a developing country.

Keyword: Rural Road Safety, Two-Lane Two-way Roads, Highway Safety Manual, Crash Prediction Models, Crash Models Calibration.

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