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 has been 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 (AASHTO Manual for Assessing 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 2009. 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. However, if a NCHRP 350 test program has already begun, that program may continue and results may be submitted to FHWA prior to January 1, 2011.
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. The States may elect to allow devices that have met NCHRP Report 350 criteria to stay in place. The States may also elect to continue to allow devices that have met NCHRP 350 installed indefinitely.
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.
MASH
The NCHRP Report 350 crash testing and evaluation criteria has been updated. The new publication will be called MASH, Manual for Assessing Safety Hardware.
As part of the rewrite of NCHRP 350, there were three main focus areas:
- Test Vehicles were updated to what’s being produced and sold today.
- Impact Condition Criteria were modified to correct inconsistencies and identify needed conditions.
- Evaluation Criteria were modified to correct subjective criteria and better define other criteria.
Up to now, previous crash testing guidelines were published as NCHRP documents, but MASH will be an AASHTO document. This will allow the state DOT’s more control of the implementation and approval processes.
Here are some of the more significant changes from the NCHRP 350 conditions to the new AASHTO MASH conditions:
- Pickup truck increases from 4,400 lbs. to 5,000 lbs.
- Small car increases from 1,800 lbs. to 2,420 lbs.
- Small car impact angle changed from 20 to 25 degrees.
- Terminal & Crash Cushion impact angle changed from 20 to 25 degrees.
- TL-4 truck increases from 17,600 lbs. to 22,000 lbs.
- TL-4 truck speed changed from 80 km/hr to 90 km/hr.
FHWA MEMOS
- September 17, 2008 SKT-SP & FLEAT-SP Standard Post Systems.
- June 1, 2008 SKT & FLEAT Universal Posts (11.5 MB)
- March 11, 2008 BEAT-SSCC Variable Lengths.
- March 8, 2005
SKT & FLEAT MGS Terminals.
- March 1, 2005
MGS Barrier.
- August 20, 2004
SKT & FLEAT Steel Post Hinged With Single 3/4" Bolt.
- July 16, 2004
BEAT-SSCC With Concrete Surface Mounted Posts.
- July 14, 2004
SKT LITE Shortened 37'-6" Long System With Wood or Steel Posts.
- December 16, 2003
Cable to W-Beam Transition Approval
- December 12, 2003
BEAT-BP Approval
- October 30, 2002
SKT Hinged Steel Post Approval
- February 22,
2002 BEAT-SSCC Approval
- February 1, 2002
BEAT-MT Approval
- August 24, 2001
FLEAT-MT Approval
- June 1, 2001
FLEAT With All 6'-3" Post Spacing
- March 23, 2001
SKT Eliminating Soil Plates From Tubes 3 Through 8
- November 9, 2000
BEAT Approval
- February 4, 2000
SKT Test Level 2 Approval
- August 27, 1999
SKT & FLEAT Steel Post Approval
- May 21, 1999
FLEAT Test Level 2 Approval
- August 28, 1998
NCHRP 350 Compliance Dates
- August 27, 1998
FLEAT Variable offset Approval
- June 10, 1998
Foundation Tube and Blockout Options
- April 2, 1998
FLEAT Approval
- April 2, 1997
SKT Approval