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FHWA Home / Safety / Roadway Departure / Longitudinal Barriers

Longitudinal Barriers

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This listing contains information on crash-worthy longitudinal barriers, such as guardrail, median barrier, and some bridge railings. (Additional information on bridge railings is found under that category.) You’ll also find information here on acceptable transition designs for attaching approach guardrails to bridge railings and for synthetic blocks used with w-beam guard rails in this listing. Temporary barriers used in work zones are included here as well.

NCHRP Report 350 establishes six test levels (TLs) for longitudinal barriers. The AASHTO MASH continues these six test levels:

TL-1, TL-2, and TL-3 require successful tests of an 1100-kg car impacting a barrier at 25 degrees, and a 2,270-kg pickup truck impacting a barrier at 25 degrees, at speeds of 50 km/h, 70 km/h, and 100 km/h, respectively.

TL-4 adds an 9,000-kg single-unit truck at 15 degrees and 90 km/h to the TL-3 matrix; TL-5 substitutes a 36,000-kg tractor/van trailer for the single-unit truck. TL-6 substitutes a 36,000-kg tractor/tank trailer.

Click on the eligibility letter number to view copies of eligibility letters, with enclosures, for each eligible device and for synthetic guardrail blocks. A direct link is provided to the websites of many manufacturers of proprietary devices.

Research is underway (October 2007) to design a short-radius guardrail section for use at intersections that will meet the requirements of NCHRP Report 350. Until a new design becomes available, the design shown in FHWA Technical Advisory T5040.32 and the drawings may be used.

Technical Advisory Archive

Page last modified on September 30, 2015.
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