CE 510: Transportation Safety Analysis

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Intersection Safety Analysis
Tualatin Valley Highway (Oregon Route 8) and SW
Murray Boulevard Beaverton, Oregon Adrian
Cantu Adam Larsen Nozomi Saito Zachary Horowitz
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Presentation Outline

• Introduction and Site Description
• Geometric Analysis
• Collision Data Analysis
• Human Factors Analysis
• Countermeasures
• Cost / Benefit Evaluation
• Proposed Actions / Conclusions / Next Steps

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Site Description - Overview
Intersection of Tualatin Valley Hwy
(OR-8) Murray Boulevard Located in City of
Beaverton, Washington County, OR 8 miles SW of
Portland Street Ownership TV Hwy Oregon
DOT Murray Washington County
TV Highway
Murray
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Site Description Land Use

• Toyota dealership - largest in Oregon
• 2 gas stations
• Shell
• Arco (with AMPM mini-mart)
• Convent / school
• Nike and Tektronix located 1 mile north of
  intersection
• Kmart

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Site Description - Geometry
TV Hwy Murray
of Lanes 3 WB, LT 3 EB, LT 2 SB, LT, RT 2 NB, LT
Median Yes, E of site None
Sidewalks / Curbs Yes Yes
Posted speed 45 mph 40 mph
Bike lanes Yes Yes
Distance between crosswalks 95 - 100 feet 150 feet

• Railroad tracks south of intersection
• Pedestrian island on NW corner
• 10 intersection skew

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Looking westbound on TV Highway
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Geometric Deficiencies

• Driveways close to intersection
• Long straights increase speed
• Low median with old reflectors
• No advance guide signs
• Very small street signs
• Bus stops close to intersection
• 10 intersection skew
• Railroad tracks
• No streetlights on Murray north of intersection
• Not enough storage in left turn pocket on Murray
  NB

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Western Pacific railroad tracks with rubber
surface
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Existing Crash Patterns
Did not yield Right of Way 65 Following too
closely 64
Rear-End Crashes 115 Turning Movement 81
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Environmental Factors
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Crash Data Time Day of Week
Afternoon peak (3 6 pm) on Friday is a bad time
to drive
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Crash Severity
The total yearly safety cost is 885,000
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Collision Diagram
Number of Total Crashes 234 Crashes/year
47 Crashes/MVMT 9.7 Data sources ODOT City
of Beaverton
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Collision Location Analysis

• Areas of Note
• Shell gas station driveway
• Cut-through traffic
• High rear-end crash locations
• Arco gas station
• AM-PM mini-mart
• Tri-met bus 62 stop
• Tri-met bus 62 stop

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Human Factors Analysis

• Two site visits
• Friday, November 25, 2005, 2pm
• Sunday, November 27, 2005, 5pm
• Drove through intersection on all approaches
• Observed all corners 100 back of intersection
• Spoke with locals
• Toyota employees, Shell gas attendant, corner
  sale sign person, Washington County Sheriff
  Deputy after traffic stop

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Human Factors Analysis

• Driver comfort level is low
• No advance warning of intersection
• Substandard to other intersections in vicinity
• Canyon/Hall, TV Hwy/153rd
• Murray/Allen Murray/Jenkins
• TV Hwy/Murray lacks mast arms, lane assignment
  markings, street signs, etc.
• RR track parallel to TV Hwy
• Crosswalk located to accommodate tracks

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Human Factors Analysis

• No Bus Turnouts
• No streetlights on SB Murray approach
• Large grass field is an unusual corner feature

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Human Factors Analysis

• High volumes
• Minimal Signage at intersection
• Poor visibility of street signs
• No lane assignment (on roadway or overhead)
• Two signals for three through lanes

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Countermeasures Proposed

• Close or relocate driveways
• Replace reflectors on existing median
• Build/improve medians
• Murray N of intersection
• TV Hwy W of intersection
• TV Hwy E of intersection

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Countermeasures Proposed

• Add 2 street lights N of intersection on Murray.
  Replace bulb on SE corner
• Add lights on the north side of TV Hwy on both
  approaches
• Optimize clearance intervals

http//www.symbolfactory.org/images/streetlights.j
pg
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Countermeasures Proposed

• Upgrade intersection signing, signal and markings
• Advance guide signs
• Overhead street signs
• Lane use arrow marking
• Intersection lane control signs
• Mast arms
• 3rd signal head on TV Hwy approaches

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Countermeasures Proposed

• Delineate left turn paths
• Lengthen left turn pocket on NB Murray

http//www.tfhrc.gov/safety/pubs/04091/images/fig1
19.jpg
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Cost / Benefit Analysis

• Yearly safety cost at intersection 885,000
• A 10 CRF would save 88,500/year
• Estimated costs of improvements 150,000
• Assume 6 interest rate for 10 years
• Calculate net present value
• Benefit / cost ratio 4.34

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Proposed Actions

• Improve intersection infrastructure to improve
  driver comfort and knowledge
• Consider closing or realigning one or more of the
  service station driveways to reduce crashes
• Repair light, improve median on TV Hwy
• Review signal timing plan to see if changes can
  be made that to improvement safety
• Figure out who is in charge of the intersection

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Conclusions

• High volume intersection has both a high
  frequency and rate of crashes, low severity
• Poor signage and appearance affects driver
  comfort and performance
• Odd geometry and land use mixes
• Lack of ownership/accountability
• Intersection should be on a priority list for
  further study / improvements it is DUE

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Next Steps

• Get additional volume, turn movement information
• Crash reduction factors for countermeasures
  proposed
• Get detailed improvement costs
• Coordinate safety improvement plan with ODOT,
  Washington County, City of Beaverton

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Acknowledgements

• Dr. Chris Monsere, PSU
• Pam Maki, City of Beaverton
• Bill Kloos, City of Portland
• ODOT
• Erin Wilson

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Questions and Comments