NCHRP 350 represents uniform guidelines for conducting full-scale crash tests for permanent and temporary highway safety features along with recommended evaluation criteria to access the test results. Products addressed in NCHRP 350 include longitudinal barriers, transitions, end terminals, crash cusions, breakaway/yielding supports, truck mounted attenuators and work zone traffic control devices. The crash performance is judged on structural adequacy, occupant risk and vehicle trajectory. The in-service evaluations of these devices are also addressed in NCHRP 350.

Note that NCHRP 350 is currently being rewritten under NCHRP Project 22-14(02).
Click here for details.

Rewrite of NCHRP 350

The rewrite of NCHRP 350 is completed and being reviewed by the AASHTO Technical Committee on Roadside Safety (TCRS). It will be an AASHTO document and the "proposed" name is AASHTO MASH-08 (AASHTO Manual for Analysis of Safety Hardware). This rewrite updated the impact condition criteria, the evaluation criteria and the test vehicles. The crash test vehicles used in NCHRP 350 are no longer being produced and heavier vehicles will be used. The expected publication date is Spring of 2008. At that time, the implementation process will begin from the FHWA and the DOT perspective.

It is anticipated that FHWA will establish a deadline date as to when newly crash tested devices will need to be tested to the update criteria. As it stands now, immediately upon publication, any new devices, including any modifications and/or revisions to NCHRP 350 compliant devices, will have to be crash tested under the new AASHTO MASH-08.

It is expected that each of the State DOT's will be able to set their own implementation dates and criteria. If that continues to be the case, each State will have the option of continuing to use 350 compliant hardware or establishing their own deadline for compliance with MASH-08. Devices that have met NCHRP Report 350 criteria may be able to stay in place and they may continue to be installed indefinitely as devices which have met NCHRP 350. The States will announce their policies as they are developed. The NCHRP 350 devices will not be grandfathered as meeting the new criteria but will always remain identified as NCHRP 350 devices unless re-tested and passed under the new criteria.

Historical Review

Document Source	Year Issued	Number of Pages	Test Vehicle & Weight
HRB #482	1962	1	4400 lb. car
NCHRP #115	1971	70	4000 to 5000 lb. cars.
NCHRP #118	1972	96	2000 & 4500 lb. cars
NCHRP #153	1974	19	2250 & 4500 lb. cars
TRC #191	1978	27	*2250 & 4500 lb. cars
NCHRP #230	1981	42	*1800 & 4500 lb. cars
NCHRP #350	1993	132	*1800 lb. car & 4400 lb. Pickup

*Large trucks also considered

Test Vehicles

NCHRP 350 Test Vehicles For Barriers	Test Vehicle Mass	Location of Vehicle Center of Mass
Small Car	1800 lb. (820 kg)	21.7 in.
Pickup Truck	4400 lb. (2000 kg)	27.6 in.
Single-Unit Van Truck	17,650 lb. (8000 kg)	66.9 in.
Tractor Van Trailer (TL-5)	79,400 lb (36000 kg)	72.8 in.
Tractor Tank Trailer (TL-6)	79,400 lb (36000 kg)	80.7 in.

Test Levels for Barriers

NCHRP 350 Test Level For Barriers	Largest Vehicle Mass	Large Vehicle Impact Speed	Impact Angle for Barriers
TL-1	4400 lb. (2000 kg)	31 mph (50 km/h)	25 deg.
TL-2	4400 lb. (2000 kg)	43 mph (70 km/h)	25 deg.
TL-3	4400 lb. (2000 kg)	62 mph (100 km/h)	25 deg.
TL-4	17,650 lb (8000 kg)	50 mph (80 km/h)	15 deg
TL-5 & TL-6	79,400 lb (36000 kg)	50 mph (80 km/h)	15 deg.

Click Here to see a Table for NCHRP 350 Test Matrix For End Terminals

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