Highway Safety Manual (HSM) into Safety Processing How to Incorporate the Highway Safety Manual (HSM) into Safety Processing Presented by Gerald Dildine, ITIS Corporation Project Review Header Slide Includes: Project Title Date of Project Review Presented To Name/Title Presented By Name/Title

Design HSM Processing Questions: How many of you currently do processing for HSM statewide? Why consider it? What does it offer Safety Records Managers? What are the benefits? What should be the role?

HIGHWAY SAFETY MANUEL Purpose of HSM processing is to provide “Predictive Crash Data”, based upon following the guidelines of the Highway Safety Manual. Within the processing of HSM, three types of predictive crashes are discussed. SPF, Predictive, and Expected

HSM CORE BENEFITS Core benefits of Predictive Crashes are to improve over the weaknesses related to using Crash History: Removes problems with “Regression to the mean” associated with using crash history. Provides values even when sparse crash data exists. Provides much more consistent “fabric” of data.

A MORE CONSISTENT DATA APPROACH Removes Misleading Spikes Removes & Fills in Gaps History - Blue HSM - Black

HSM ANCILLARY BENEFITS A number of ancillary benefits come through artifacts from processing

BASIC STEPS IN HSM PROCESSING CRASH HISTORY ROADWAY SPF PREDICTIVE EXPECTED Integrate roadway and crash elements statewide Process SPFs with variations for each facility and severity Factor CMFs and calibrate SPFs Combine model with history

HSM PROCESSING 13 FACILITY TYPES CRASH HISTORY SPF PREDICTIVE EXPECTED ROADWAY 20 SPFs 24 CMFs When processing, HSM forces us to organize our data better, and produces calculations which are reusable downstream 18 ROADWAY DATA ELEMENTS

Roadway Characteristics HSM PRODUCTS HSM PROCESSING Predicted Crashes Facility Types CMFs/ Risks Safety Indexes Rankings Hot Spots Products / Byproducts Downstream Products Assembly and calculations result in very useful byproducts, Downstream calculations make use of HSM processing Roadway Characteristics

HSM ANCILLARY BENEFITS Ancillary benefits of HSM processing include the following: Organization and consolidation of required supporting roadway characteristics. Organization of roadways into facility types, which enables better comparative analysis. Exposure of the most significant risks associated with each roadway section. Improvements to downstream processing of scoring indexes and rankings.

ROADWAY CHARACTERISTICS Facility type Lane width Shoulder width and type Horizontal curve (radius and length) Superelevation Vertical grade Lighting Approach density Speed limit Center-line rumble strip Passing lanes TWLTL Roadside hazard rating

FACILITY TYPES RuFl2 Rural, Flat, 2 lane RuFl2+ Rural, Flat, 2+ lane RuFlIB Rural, Flat, Interstate (both directions) RuFlID Rural, Flat, Interstate (Dec direction) RuFlII Rural, Flat, Interstate (Inc direction) RuMt2 Rural, Mountainous, 2 lane RuMt2+ Rural, Mountainous, 2+ lane RuMtIB Rural, Mountainous, Interstate (both directions) RuMtID Rural, Mountainous, Interstate (Dec direction) RuMtII Rural, Mountainous, Interstate (Inc direction) RuRo2 Rural, Rolling, 2-lane RuRo2+ Rural, Rolling, 2+ lane RuRoIB Rural, Rolling, Interstate (both directions) RuRoID Rural, Rolling, Interstate (Dec direction) RuRoII Rural, Rolling, Interstate (Inc direction) Ur Urban UrIB Urban Interstate (both directions) UrID Urban Interstate (Dec direction) UrII Urban Interstate (Inc direction)

CMFs/RISKS Lane width Shoulder width and type Horizontal curve (radius and length) Superelevation Vertical grade Approach density Center-line rumble strip Passing lanes TWLTL Roadside hazard rating Others

EXPECTED CRASHES Expected crashes are the primary result from HSM processing, but the work doesn’t end there! Performing HSM processing across a highway network can be used to develop a more consistent reliable database for crash numbers. Expected crashes can be used for scoring and ranking of segments. Cmfs can be used for risk calculations Expected crashes can be used for benefits calculations

SAMPLE DOWNSTREAM FUNCTIONS SAFETY SCORING SAFETY BENEFIT RISK DETAILS

SAMPLE PRODUCTS: CRASH PROFILE RANKING EXPECTED CRASHES CRASHES LAST 5 YEARS (BY SEVERITY) PMPY

SAMPLE PRODUCTS: ROADWAY PROFILE POSTED SPEED LIMIT TERRAIN URBAN RURAL ACCESS LOCATIONS AND DENSITY SHOULDER WIDTH TOP PAVED

SAMPLE PRODUCTS: NUMBER OF LANES LANE CONFIGURATION TRAFFIC VOLUME TRUCK PERCENT TRAFFIC VOLUME CURVE ADVISORY ROADSIDE HAZARD RATING (1-7)

SAMPLE PRODUCTS: FRICTION PAVEMENT RATING RUTTING

BENEFITS Project decision-making Hot spot creation Systemic analysis Studies Overall benefits come in the form of providing better consistent information which avoids some of the pitfalls of crash history Better results from network screening and/or hot spot development A more constent fabric of for statewide systemic analysis and specific studes

WHERE DO WE GO FROM HERE? HSM is deployed into the Department’s Safety Management System (Economic Analysis) Still more work to do in finalizing Intersections. Possible work in Interchanges and perhaps roundabouts. Still completing full inclusion in to analytics processing.

A SPECIAL THANK YOU TO: Wyoming DOT, for the opportunity to work on HSM. Joe McCarthy, for use of some slide information.