Research Papers

Collision prediction for two lane rural roads using IHSDM: A Canadian experience

Filename Marleau.pdf
Filesize 207 KB
Version 1
Date added June 6, 2010
Downloaded 1 time/fois
Category 2010 CMRSC XX Niagara
Tags Session 3C
Author/Auteur Matthew Marleau, Eric Hildebrand


A study at the University of New Brunswick was performed on the transferability of the collision prediction capabilities of Interactive Highway Safety Design Model (IHSDM) within a rural Canadian context. Collision prediction models are generally created with data that intrinsically reflect geographic, environmental, and operational characteristics unique to a particular region. The transferability of a model to a different area can sometimes be problematic. The IHSDM model has been developed with two levels of calibration that are intended to facilitate its widespread application. This study evaluated both the 2008 and 2009 (beta) versions of the collision prediction models for two lane rural roads embedded in IHSDM. A sample of seventy-five rural two-lane road segments from the province of New Brunswick was analyzed to evaluate the model’s performance. The analysis compared the predicted collision frequencies with the empirical collision data provided by the New Brunswick Department of Transportation. Results of the study have shown that overall the model performs poorly when compared with the average number of observed collisions. Predicted collision frequencies for all test sites combined were over- estimated by 38 to 78 percent (depending on the level of calibration employed). Goodness-of-fit testing including mean absolute deviation, mean prediction bias, and R² showed that the model does not perform well within a Canadian context and that the calibration methods need refining. Model fits described by coefficient of determination, R², ranged from only 0.001 to 0.255.

Matthew Marleau and Eric Hildebrand