00756145

Component

https://doi.org/10.3141/1635-15

http://scholar.google.com...uyen&publication_year=1998

The more advanced methods for identifying unsafe intersections and evaluating the safety effect of treatment are based on an Empirical Bayesian framework that requires the use of safety performance functions relating the expected safety of an intersection to characteristics such as traffic flow. Aggregate and disaggregate models were developed to estimate the safety performance of three-legged and four-legged signalized intersections on Ontario provincial roads. Models were disaggregated by time period, accident severity, and environment class. Two levels of models were calibrated for different levels of data availability and model requirements. For Level 1, the safety of an intersection was estimated as a function of the sum of all entering flows; separate estimates were obtained for rear-end, right angle, and turning movement accidents, the three most prominent impact types. In Level 2, specific patterns were defined by the movements of involved vehicles prior to collision, and accidents for the main patterns at four-legged intersections were estimated as a function of flows relevant to each pattern. Aside from the theoretical aspects, the models provide a basis for comparison with available models for other jurisdictions. There are some novel aspects in that unlike most models available for roads outside municipalities, the ones presented here do allow for safety estimates to be disaggregated by time period, accident severity, impact type, and accident pattern. Moreover, the calibrated models can be used in an Empirical Bayesian framework to estimate the safety of an individual intersection. This is an important feature generally lacking in available models.

This paper appears in Transportation Research Record No. 1635, Safety Analysis Related to Highway Design, Crash Costs, and Traffic Records Systems; Methodologies for Evaluating Safety Improvements.

English

p. 113-120

1998

Transportation Research Record

0309065070

Figures (1) ; References (15) ; Tables (11)

Bayes' theorem; Crash severity; Crash types; Disaggregate analysis; Empirical methods; Evaluation and assessment; Improvements; Safety; Signalized intersections; Time intervals; Traffic crashes; Traffic flow; Travel patterns

Traffic patterns

Ontario (Province)

Ontario (Province)

Highways; Safety and Human Factors; I82: Accidents and Transport Infrastructure

TRIS, TRB, ATRI

Nov 10 1998 12:00AM

• ACCIDENT MODELS FOR TWO-LANE RURAL SEGMENTS AND INTERSECTIONS
• ALLOCATING THE COSTS OF MOTOR VEHICLE CRASHES BETWEEN VEHICLE TYPES
• APPLYING THE ORDERED PROBIT MODEL TO INJURY SEVERITY IN TRUCK-PASSENGER CAR REAR-END COLLISIONS
• CONFLICT ANALYSIS FOR DOUBLE LEFT-TURN LANES WITH PROTECTED-PLUS-PERMITTED SIGNAL PHASES
• CONSIDERATION OF BOLLARD TREATMENT AT EXIT GORE AREAS
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• DEVELOPMENT OF SAFETY-BASED LEVEL-OF-SERVICE PARAMETERS FOR TWO-WAY STOP-CONTROLLED INTERSECTIONS
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• EFFECTS OF A TOWAWAY REPORTING THRESHOLD ON CRASH ANALYSIS RESULTS
• EVALUATING MEDIAN CROSSOVER LIKELIHOODS WITH CLUSTERED ACCIDENT COUNTS: AN EMPIRICAL INQUIRY USING THE RANDOM EFFECTS NEGATIVE BINOMIAL MODEL
• EXPLORATORY MULTIVARIABLE ANALYSES OF CALIFORNIA DRIVER RECORD ACCIDENT RATES
• INVESTIGATION OF NATIONAL HIGHWAY SYSTEM ROADWAYS IN THE HIGHWAY SAFETY INFORMATION SYSTEM STATES
• INVESTIGATION OF THE EFFECTIVENESS OF BOULEVARD ROADWAYS
• POLICE REPORTING OF PEDESTRIANS AND BICYCLISTS TREATED IN HOSPITAL EMERGENCY ROOMS
• PREDICTING VEHICLE OCCUPANCIES FROM ACCIDENT DATA: AN ACCIDENT SEVERITY APPROACH
• PREDICTION MODELS FOR TRUCK ACCIDENTS AT FREEWAY RAMPS IN WASHINGTON STATE USING REGRESSION AND ARTIFICIAL INTELLIGENCE TECHNIQUES
• SAFETY BENEFITS OF SPIRAL TRANSITIONS ON HORIZONTAL CURVES ON TWO-LANE RURAL ROADS
• SAFETY EVALUATION OF ALTERNATIVE SIGNAL HEAD DESIGN
• SEASONAL VARIATIONS IN THE AGE-RELATED COLLISION RISK OF ONTARIO DRIVERS
• SPOT SPEED ANALYSIS ON URBAN ROADS IN RIYADH
• TWO PROBLEMS OF AVERAGING ARISING IN THE ESTIMATION OF THE RELATIONSHIP BETWEEN ACCIDENTS AND TRAFFIC FLOW