Extending the Highway Safety Manual (HSM) framework for traffic safety performance evaluation

2014 ◽  
Vol 64 ◽  
pp. 146-154 ◽  
Author(s):  
Narayan S. Venkataraman ◽  
Gudmundur F. Ulfarsson ◽  
Venky N. Shankar
Keyword(s):  
Performance Evaluation ◽  
Traffic Safety ◽  
Highway Safety ◽  
Safety Performance ◽  
Highway Safety Manual

Calibration of the Highway Safety ManualGiven Safety Performance Functions for RuralMultilane Segments and Intersections in Kansas

2017 ◽  
Author(s):  
Syeda Rubaiyat Aziz ◽  
Sunanda Dissanayake
Keyword(s):  
Safety Evaluation ◽  
Highway Safety ◽  
Safety Performance ◽  
Regression Coefficients ◽  
Local Conditions ◽  
Crash Prediction ◽  
Highway Safety Manual ◽  
Satisfactory Level ◽  
Safety Performance Functions ◽  
Predictive Methods

The Highway Safety Manual (HSM) provides models and methodologies for safety evaluation and prediction of safety performance of various types of roadways. However, predictive methods in the HSM are of limited use if they are not calibrated for local conditions. In this study, calibration procedures given in the HSM were followed for rural segments and intersections in Kansas. Results indicated that HSM overpredicts fatal and injury crashes and underpredicts total crashes on rural multilane roadway segments in Kansas. Therefore, existing safety performance functions (SPFs) must be adjusted for Kansas conditions, in order to increase accuracy of crash prediction. This study examined a way to adjust HSM calibration procedures by development of new regression coefficients for existing HSM-given SPF. Final calibration factors obtained through modified SPFs indicated significant improvement in crash prediction for rural multilane segments in Kansas. Additionally, obtained calibration factors indicated that the HSM is capable of predicting crashes at intersections at satisfactory level.

scholarly journals Engineering Solutions to Enhance Traffic Safety Performance on Two-Lane Highways

2015 ◽  
Vol 2015 ◽  
pp. 1-7
Author(s):  
Lina Wu ◽  
Jiangwei Chu ◽  
Yusheng Ci ◽  
Shumin Feng ◽  
Xingwang Liu
Keyword(s):  
Traffic Safety ◽  
Empirical Bayes ◽  
Practical Importance ◽  
Cost Effective ◽  
Highway Safety ◽  
Safety Performance ◽  
Highway Traffic ◽  
Research Attention ◽  
Research Perspectives ◽  
Sight Distance

Improving two-lane highway traffic safety conditions is of practical importance to the traffic system, which has attracted significant research attention within the last decade. Many cost-effective and proactive solutions such as low-cost treatments and roadway safety monitoring programs have been developed to enhance traffic safety performance under prevailing conditions. This study presents research perspectives achieved from the Highway Safety Enhancement Project (HSEP) that assessed safety performance on two-lane highways in Beijing, China. Potential causal factors are identified based on proposed evaluation criteria, and primary countermeasures are developed against inferior driving conditions such as sharp curves, heavy gradients, continuous downgrades, poor sight distance, and poor clear zones. Six cost-effective engineering solutions were specifically implemented to improve two-lane highway safety conditions, including (1) traffic sign replacement, (2) repainting pavement markings, (3) roadside barrier installation, (4) intersection channelization, (5) drainage optimization, and (6) sight distance improvement. The effectiveness of these solutions was examined and evaluated based on Empirical Bayes (EB) models. The results indicate that the proposed engineering solutions effectively improved traffic safety performance by significantly reducing crash occurrence risks and crash severities.

scholarly journals Calibration of the Highway Safety Manual and the SafetyAnalyst Methodologies for Ontario Highways

2021 ◽  
Author(s):  
Ali Sabbaghi
Keyword(s):  
Road Safety ◽  
Goodness Of Fit ◽  
Highway Safety ◽  
Safety Performance ◽  
Data Set ◽  
Rural Highways ◽  
Part C ◽  
Highway Safety Manual ◽  
Safety Performance Functions ◽  
Central Regions

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.

Application of Highway Safety Manual Method for Ramp Crash Prediction to Loop and Diamond Ramps

2017 ◽  
Vol 2636 (1) ◽  
pp. 43-52 ◽  
Author(s):  
Darren J. Torbic ◽  
Douglas W. Harwood ◽  
Karin M. Bauer
Keyword(s):  
Prediction Method ◽  
Highway Safety ◽  
Safety Performance ◽  
Prediction Methods ◽  
Crash Prediction ◽  
Crash Data ◽  
Manual Method ◽  
Highway Safety Manual ◽  
Separate Calibration

The AASHTO Highway Safety Manual (HSM) now includes crash prediction procedures for ramps. Research was undertaken to assess how well these new crash prediction methods represented the safety performance of two ramp types with distinctly different geometrics: loop ramps and diamond ramps. The HSM crash prediction procedures were applied to 235 loop ramps and 243 diamond ramps in two states—California and Washington—and the results were compared with 5 years of actual crash data for the same ramps. The results indicate that the HSM crash prediction method can be applied to both loop and diamond ramps, but to compare the safety performance of these two ramp types properly, separate calibration of loop and diamond ramps is needed.

scholarly journals Calibration of the Highway Safety Manual and the SafetyAnalyst Methodologies for Ontario Highways

2021 ◽  
Author(s):  
Ali Sabbaghi
Keyword(s):  
Road Safety ◽  
Goodness Of Fit ◽  
Highway Safety ◽  
Safety Performance ◽  
Data Set ◽  
Rural Highways ◽  
Part C ◽  
Highway Safety Manual ◽  
Safety Performance Functions ◽  
Central Regions

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.

Safety Performance of Crossroad Ramp Terminals at Single-Point and Tight Diamond Interchanges

2021 ◽  
pp. 036119812110299
Author(s):  
Darren J. Torbic ◽  
Richard J. Porter ◽  
Jeff Gooch ◽  
Kristin Kersavage
Keyword(s):  
Urban Areas ◽  
Prediction Models ◽  
Single Point ◽  
Highway Safety ◽  
Safety Performance ◽  
Crash Prediction ◽  
Highway Safety Manual ◽  
Predictive Methods ◽  
Diamond Interchanges ◽  
Crash Prediction Models

Single-point diamond interchanges and tight diamond interchanges are two alternative interchange types that are considered in urban areas where right-of-way is usually limited. The Highway Safety Manual First Edition predictive methods for freeways and interchanges are capable of estimating the safety performance of freeway mainline, freeway-ramp terminal, and ramp proper segments associated with these interchange types. However, limited research has been conducted to predict and compare the safety performance of the crossroad ramp terminals for these two alternative interchange designs, as would be necessary for a performance-based approach to interchange alternatives analysis. Planners, designers, and safety managers would benefit from having tools to compare the safety performance of these crossroad ramp terminals to make more informed decisions about their use and application in the urban environment. Research was undertaken with the objective of developing new intersection crash prediction models for crossroad ramp terminals at single-point diamond interchanges and crossroad ramp terminals at tight diamond interchanges. In general, it was found that the crash prediction models for crossroad ramp terminals at single-point diamond interchanges predicted more crashes than the models for crossroad ramp terminals at tight diamond interchanges in higher volume conditions. The differences were primarily driven by the property-damage-only crash predictions. Comparisons of the crash prediction models suggested that the two sets of models appear compatible and provide reasonable results over the range of applicable traffic volume conditions.

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