NCHRP 350 & MASH
NCHRP 350 and MASH represent 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 and MASH include longitudinal barriers, transitions, end terminals, crash cushions, 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 and MASH. Note that NCHRP 350 has been rewritten under NCHRP Project 22-14(02). Click here for details.
MASH has been adopted and published. Click here to see a summary of the differences between MASH and NCHRP 350 and the AASHTO/FHWA joint implementation plan.
Rewrite of NCHRP 350
The rewrite of NCHRP 350 is completed. It was reviewed by the AASHTO Technical Committee on Roadside Safety (TCRS) and is an AASHTO document. It's called The AASHTO Manual for Assessing Safety Hardware (MASH). This rewrite updated the test vehicles, the impact condition criteria, and the evaluation criteria. The differences between MASH and NCHRP 350 along with the AASHTO/FHWA joint implementation plan can be seen at the above link.
MASH
The NCHRP Report 350 crash testing and evaluation criteria has been updated and the new publication is called MASH, The AASHTO 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.
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
- FHWA letter with FAQs (November 2010)
- FHWA letter with FAQs (May 2010)
- FHWA letter CC-88D (January 29, 2010)
- FHWA letter CC-88C (December 10, 2009)
- September 17, 2008 SKT-SP & FLEAT-SP Standard Post Systems
- June1, 2008 SKT & FLEAT Universal Posts
- 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
Click here for important Grading & Length of Need information
Historical Review
| Document Source | Year Issued | # 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. |