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Transportation Research Board
2006 Annual Meeting Trip Report

Gary Gauthier is the Caltrans representative on the TRB AFB20 Committee on Roadside Safety Design. He attended the annual meeting January 2006, and has listed the following items of interest. You may contact him at gary.gauthier@dot.ca.gov if you would like further information on any the items. A full trip report is available on request.

  1. A Collision Performance Side Impact Modification (CPSI) device is available that can be used on slotted rail and extruder end terminals to provide safer performance in side impacts. May be desired to be installed in locations where side impacts have occurred or are potential.
     
  2. The Midwest Guardrail System (MGS), that features improved performance in pickup truck impacts over standard guardrail (Metal Beam Guardrail), has been fully tested, including the transition and end treatment. Waiting on approval of the transition by FHWA – length of need and end treatment have been approved. Recommend that Caltrans investigate adopting this system for MBGR.
     
  3. NCHRP Projects starting this year:
    • 22-23, “Criteria for Restoration of Longitudinal Barriers”, which will develop procedures for maintaining barriers, has been approved and will be started this year. May be useful for Maintenance in maintaining guardrail.
    • 22-21, “Median Cross-Section Design for Rural Divided Highways”
    • 22-22, “Placement of Traffic Barriers on Roadside and Median Slopes
       
  4. A useful tool, Casewise Visual Evaluation, used in a University of Arizona study for selecting aesthetic soundwalls, uses “customer” electronic voting and a software analyzer that provides equitable support in aesthetic decisions. This may be helpful in our current aesthetic barrier projects.
     
  5. The Halco X-44 lightweight steel post for guardrails has been crash tested and is more forgiving in wheel snagging, but limits deflections comparably to standard steel or wood. Costs are supposed to be comparable to standard steel posts, and might be worth investigating.
     
  6. The Roadside Safety Analysis Program (RSAP) has been modified to use in designing effective and safe installations of portable concrete barrier. May be helpful to district design, traffic and construction engineers.
     
  7. TTI has developed the X-Bolt portable concrete barrier that has lateral deflections of 19” using 30’ sections, but with no ground anchoring. Construction maybe interested in using this design where low deflections are needed but anchoring is difficult or not cost-effective.
     
  8. University of Nebraska, Lincoln has developed a transition design from free-standing portable concrete barrier to fully anchored barrier. This may be useful for Caltrans if we design our own transition.
     
  9. The new crash test guidelines to replace NCHRP Report 350 will include a more severe 8000-kg truck test for TL-4. It will be tested at 100 km/hr instead of 80 to present a higher impact severity than the 2000-kg pickup truck. This will provide a stronger TL-4 barrier than one rated at just TL-3. Currently a TL-4 barrier only needs to be as strong as the TL-3, but must be designed to prevent the 8000-kg truck from rolling over the top.