Murray Boulevard and Farmington Road Intersection Sirisha Kothuri Wei Feng Ping Guo Meead Saberi CEE 550 Transportation Safety Analysis

Outline Introduction Site Description Crash Data Analysis Literature Review Countermeasures Cost/Benefit Analysis Recommendations

Introduction Map of Intersection Murray Boulevard 2 lane undivided Runs N-S Farmington Road 2 lane undivided Runs E-W Intersection City of Beaverton 4-leg signalized Slight skew High Volume

Aerial View of the Intersection Site Description - I Murray Blvd Farmington Road Apt7-Eleven Apt

Site Description - II Signal at Intersection Illumination at Intersection Barrier at Intersection Pavement Markings at Intersection

Site Description - III Speed Limit Sign on FarmingtonSpeed Limit Sign on Murray Driveways near IntersectionSchool Zone Signs

Site Description - IV Heavy Vehicles Queue Spillover to Adjacent Intersection

Volume Source: City of Beaverton

Crash Data Analysis Oregon Transportation Safety Data Archive (ortsda) Crash File Crashes for 4 Years ( ) at intersection Vehicle File Information about vehicles involved in crashes at intersection Participant File Information about drivers involved in crashes at intersection Crash Patterns at the Intersection Time of Day Type of Crash Severity Weather Light Conditions Driver Characteristics Residence Status Gender Age

Time of Day

Type of Crash

Crash Severity

Crash Cause

Collision Diagram Murray Blvd Farmington Rd

Literature Review Rear End Crashes –Most common type at signalized intersections –Account for one-third of all reported crashes in US –Mostly PDO, sometimes severe injuries and fatalities occur Causes –Driver Behavior – Inattentive driving, smaller headways –Driver Age and Gender –Heavy Traffic Volumes –Dilemma Zone

Dilemma (Indecision) Zone Source: Heng Wei, Characterize Dynamic Dilemma Zone and Minimize its Effect at Signalized Intersections, Ohio Transportation Consortium (OTC), 2008

Dilemma (Indecision) Zone

Countermeasures 1.Reduce speed limit on approaches 35 mph on Murray Blvd 30 on Farmington Road Pros Reduction in all types of crashes Cons Increase in delay Diversion of vehicles to other streets

Countermeasures 2. Advance Signal Warning Signs Murray Blvd & Farmington Rd Pros Reduction in Rear End Crashes Low cost Easy Implementation Cons

Countermeasures 3.Improve Signal Timing Optimize to ITE Standards Pros Reduces Rear End PDO crashes Cons Increases Fatal and Injury crashes

Countermeasures 4.Coordinated Signals Coordinate adjacent intersections Pros Allows progression of vehicles Reduces all types of crashes Cons Hard to implement

Cost Benefit Analysis Select Countermeasures –For each countermeasure, extract CRF –Calculate reduction in crashes –Calculate annual benefits and costs –Assume discount rate of 4% –Calculate NPV = NPVB – NPVC –Rank countermeasures in decreasing order of NPV

Cost Benefit Analysis Cost of All Crashes at Intersection

Cost Benefit Analysis 1. Reduce vehicle’s approach speed limit

Cost Benefit Analysis 2. Advance Signal Warning Signs

Conclusions & Recommendations Rear-end crashes are common at signalized intersections. Typical causes Driver Behavior Driver Age & Gender Heavy Traffic Volumes Dilemma Zone Countermeasures Ranking Based on B/C Analysis 1. Install Advance Signal Warning Signs 2. Reduce vehicle’s approach speed limit 3. Signal Coordination

Acknowledgements Dr. Chris Monsere, PSU Jabra Khasho, City of Beaverton Baotu Ho, City of Beaverton