Abstract
SafetyAnalyst and the Highway Safety Manual (HSM) are two tools that are expected to revolutionize highway safety analyses. A key issue that allows SafetyAnalyst and HSM to become the new standards in road safety engineering is the calibration of their safety performance functions (SPFs) across time and jurisdictions. In this study, the methodologies of SafetyAnalyst and HSM are calibrated for Ontario to evaluate the effective transferability of their SPFs to local topographical conditions. A SafetyAnalyst calibration has been completed for Ontario highways and freeways, intersections, and ramps for six years (1998-2003) of traffic and accident counts. A data set which consists of 78 kilometres of rural two-lane two-way highways and 71 three- and four-legged stop controlled intersections located in the eastern and central regions of the Ministry of Transportation of Ontario (MTO) with six years (2002 to 2007) of traffic volume and collision counts has been used to evaluate the HSM SPFs to Ontario data. Several goodness-of-fit (GOF) measures are computed to assess the transferability and suitability of the crash models for applicability in Ontario. The study suggests that while most of the SafetyAnalyst SPFs for highways and ramps are not adaptable to Ontario data, the recalibrated SafetyAnalyst SPFs for intersections and also the recalibrated HSM Part C predictive models for two-lane rural highways and intersections provide satisfactory results in comparison to the crash models developed specifically for Ontario. Finally, this research highlights the substantial need for future improvements in data quality for more reliable safety performance estimations and evaluations.
Highlights
According to Transport Canada (2006), almost 22 million people drive an average of 16,000 km per year on Canadian roads
safety performance functions (SPFs) have different important uses in transportation safety which make their proper calibration an essential task. Despite their significance, there are a relatively small number available because of the complexity of their calibration. This complexity is due to three primary reasons, which is the need for high-quality traffic, collision, and geometric data, several years of collision data to assemble a large enough sample size, and there is the complexity of the actual calibration process itself
The Highway Safety Manual (HSM) calibration procedure was applied to OPFs, SafetyAnalyst SPFs, and HSM SPFs for several facility types and road networks
Summary
According to Transport Canada (2006), almost 22 million people drive an average of 16,000 km per year on Canadian roads. An average of 8 deaths, 600 injuries, and 1,600 crashes take place every day on Canadian roads which cost $27,000,000 to society This alone testifies the significance of transportation safety. The traditional approaches, used alone, have critical weaknesses in estimating the current or the future safety performance of a network, facility, or individual site. These methods have been using average crash frequencies, statistical models based on regression analyses, before-after studies, and engineering judgments to predict the safety performance of a site (Harwood et al 2000). A quick description of these traditional methods will be provided below, and a new method, the “safety performance function (SPF)” approach which contains elements of each of these traditional methods, will be described
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
