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Oklahoma’s Experience with Wire Rope Safety Fence

Oklahoma’s Experience with Wire Rope Safety Fence. In Oklahoma, median crossover accidents have increased. State Under Pressure

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Oklahoma’s Experience with Wire Rope Safety Fence

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  1. Oklahoma’s Experience with Wire Rope Safety Fence

  2. In Oklahoma, median crossover accidents have increased. • State Under Pressure • In response to the increase in median crossover accidents, in 2006 ODOT initiated a program to install wire rope safety fence at critical locations through out Oklahoma.

  3. First Installation in OklahomaLake Hefner Parkway • Opened in 1991 • 6 lane divided highway approximately 44’ grass median; no highway lighting • 108,000 ADT (2000) • Speed limit 65 mph • Site of 185 Crossover accidents – 6 Fatal, 77 injured from June 1, 1997 through May 31, 2001

  4. Lake Hefner Parkway • Considered three options: concrete median barrier, strong-post guardrail and cable barriers. • Cost/mile for each option: • Concrete median barrier: $500,000 • Double-face W-beam guardrail: $105,000 • Wire Rope Safety Fence-Socketed system: $84,000 • Selected the Brifen wire rope safety fence with socketed system.

  5. Brifen Wire Rope Safety Fence Background • Developed by Brifen Ltd. in the United Kingdom in 1989 • In use in over 30 countries and 1/2 of the states • NCHRP-350 TL3 approved by FHWA in March 2001 • Licensed Brifen USA, Inc. in November 2002 Picture 3 Picture 1 Picture 2

  6. Brifen Wire Rope Safety Fence Features • 10’-6” (3.2 m) Post Spacing • Four Rope High Tensioned System • Aesthetically Appealing • Minimal Deflection • Socketed System – Easy to Repair • Capable of Long Segment Length Between Anchors • Proven Crash Testing and Real World Experience

  7. Brifen Wire Rope Safety Fence Application • Center medians • May be placed on either side of roadway • Basic Design Criteria • Recommend slopes of 6:1 or flatter • Predictability of vehicle at impact with WRSF at normal height with all wheels still on ground • Deflection less than 8 feet • End anchors can be miles apart

  8. Brifen Wire Rope Safety Fence Benefits • Economical Installation • Socketed Line Post System – Typical $15.95 LF • Driven Line Post System – Typical $ 12.00 LF • (Installed Costs) • Low Occupant Ridedown Acceleration • NCHRP-350 TL3 Maximum - 20 G’s • Brifen 898 kg Car - 4.0 G’s • Brifen 2000 kg Pickup - 2.86 G’s

  9. Brifen Wire Rope Safety Fence Benefits (Continued) • High Tensioned Prestressed Ropes • Reduced dynamic deflection • Reduced length of barrier damaged in crash • Secondary hits successful between repairs • Low maintenance costs • Wire Rope Safety Fence Open Design • Visibility unobstructed through WRSF • Debris blows through Fence • Snow drift problem reduced • Drainage unaffected by Wire Rope Safety Fence

  10. Brifen Wire Rope Safety Fence • Oklahoma City, OK - Lake Hefner Parkway • 1000 Linear Feet Installation in September 2000 • 7 Mile Installation in July 2001 Picture 1 Picture 2 Picture 3

  11. Brifen Wire Rope Safety FenceLake Hefner Parkway Specifics • Wire Rope Safety Fence installed in median 2 feet from existing southbound shoulder • Asphalt widening under WRSF for weed barrier • Seven miles in length

  12. Accident History—2001 to 2006 • Since 2001, over 430 hits. In 2/3 of those hits, driver kept going. • Injuries: • Reduced from 77 injuries in 2001 to 8 injuries in 2006. • Fatalities: • Reduced from 6 fatalities in 2001 to 1 fatality in 2006.

  13. Brifen Wire Rope Safety FenceLake Hefner Parkway Photos Picture 2 Picture 1

  14. Brifen Wire Rope Safety FenceLake Hefner Parkway Impacts August 1, 2001 To December 1, 2002 Total Impacts: 141 Total Posts: 665 Avg Posts/Impact: 4.71

  15. Brifen Wire Rope Safety FenceLake Hefner Parkway Impacts August 1, 2001 To December 1, 2002 Northbound Impacts: 44 Posts: 200 Average: 4.54 Southbound Impacts: 97 Posts: 465 Average: 4.79 Picture 1 Picture 2

  16. Brifen Wire Rope Safety FenceLake Hefner Parkway More Impacts Picture 3 Picture 1 Picture 2

  17. Brifen Wire Rope Safety FenceLake Hefner Parkway More Impacts Picture 3 Picture 1 Picture 2

  18. Brifen Wire Rope Safety FenceTypical Vehicle Damage Picture 1 Picture 2 Picture 3

  19. Brifen Wire Rope Safety FenceTypical Vehicle Damage (Continued) Picture 1 Picture 2 Picture 3 Picture 4

  20. Brifen Wire Rope Safety FenceSocketed System • Typical repair time under 30 minutes • Only one person required • No specialized tools (except tension meter on occasion) • No lane closures required for heavy equipment • Inexpensive – normally just a few posts • There has been no damage to ropes or rigging screws in over 430+ impacts Picture 1 Picture 2

  21. Brifen Wire Rope Safety FenceSocketed Option – Easy Repair Picture 2 Picture 1

  22. I-35 in Norman: • Prior to wire rope safety fence installation: • 7 fatalities, 39 injured (3 years) • Since installation (2005): NO fatalities, NO injuries. 140+ hits and several semi hits. • Installed in the center of the median; required a 6:1 slope or flatter; adjustments to the median drainage structures.

  23. Picture 2 Picture 1

  24. 10 minutes, no re-tensioning

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