MASH comes up constantly in TMA specifications, state DOT approval lists, and bid documents — but the actual technical content behind the acronym is less well understood than it should be. Fleet managers and project engineers who know what MASH tests, what it replaced, and what it requires operationally are better positioned to spec equipment correctly, avoid compliance gaps on federal-aid projects, and respond when an inspector or owner's rep asks questions in the field.
What MASH Is and Where It Comes From
The Manual for Assessing Safety Hardware is a joint publication of the American Association of State Highway and Transportation Officials (AASHTO) and the Federal Highway Administration (FHWA). It establishes the crash-test protocols, evaluation criteria, and documentation standards that roadside safety hardware must meet for use on federally funded projects.
MASH replaced NCHRP Report 350, which had been the governing standard since the mid-1990s. AASHTO published the first edition of MASH in 2009 (MASH 2009) and a second edition in 2016 (MASH 2016). FHWA's implementation agreement set December 31, 2019 as the manufacture-date cutoff: temporary work-zone devices, including TMAs, manufactured after that date must be MASH 2016 compliant. Devices manufactured on or before that date and compliant with NCHRP 350 or MASH 2009 may continue in service through their normal useful life. The critical word is "manufactured," not "installed" — a pre-2020 NCHRP 350 TMA that is still in good condition can continue to be used, but a new purchase must be MASH 2016 compliant.
Key Differences from NCHRP 350
NCHRP 350 and MASH test largely the same scenarios, but MASH introduced several changes that matter for TMA operators:
- Heavier test vehicles: MASH uses a 2,420-lb small car (1100C) and a 5,000-lb pickup truck (2270P) as the primary impacting vehicles for TL-1 through TL-3. NCHRP 350 used lighter vehicle classes — a 1,800-lb small car (820C) and a 4,400-lb pickup (2000P) — so the heavier MASH vehicles generate meaningfully higher impact energy at the same speed.
- Higher impact speeds in some test levels: TL-3 specifies a 62 mph (100 km/h) impact, consistent with 350, but the vehicle mass change means energy at impact is meaningfully higher under MASH protocols.
- Expanded evaluation criteria: MASH added criteria around occupant risk factors and post-impact behavior of the test vehicle that NCHRP 350 didn't capture in the same way.
- Documentation requirements: MASH requires more rigorous test documentation, including video from multiple angles, which makes it easier to audit compliance claims.
The practical effect is that some hardware that passed NCHRP 350 testing would not pass MASH testing at the same test level, particularly at TL-3.
Test Levels and What They Mean for TMAs
MASH defines six test levels (TL-1 through TL-6), with increasing speed and/or vehicle mass. For truck-mounted attenuators, the relevant test levels are:
- MASH TL-2: 44 mph (70 km/h) impact with the 5,000-lb pickup truck (designated 2270P). Appropriate for low-speed work zones, typically urban or residential environments with posted speed limits at or below 45 mph.
- MASH TL-3: 62 mph (100 km/h) impact with the 5,000-lb pickup truck (2270P). Required for highway and interstate work zones, including any project on a federal-aid route with posted speeds above 45 mph.
Most state DOTs require MASH TL-3 certification for TMA trucks used on high-speed roadways. Some states specify TL-3 as the minimum for all projects, regardless of posted speed, to avoid ambiguity in the field.
When reviewing a TMA's certification documentation, look for:
- The specific MASH edition (2009 or 2016) — some states require 2016 edition testing
- The test level (TL-2 or TL-3)
- Whether the certification applies to the attenuator model as mounted on a specific host vehicle class, or is configuration-independent
FHWA Requirements on Federal-Aid Projects
FHWA's formal policy on MASH compliance makes clear that after the December 2019 transition date, new hardware on federal-aid projects must meet MASH. The policy applies to:
- New installations of permanent roadside hardware
- New installations of temporary work-zone hardware, including TMAs used on federal-aid construction projects
- Replacement of crashed or worn-out hardware on active projects
State DOTs have incorporated MASH requirements into their standard specifications and approved product lists. If a product isn't on the state's accepted product list for TMAs, you cannot use it on a state DOT project regardless of what the manufacturer's marketing materials say. Confirm current list status with the relevant state DOT before purchasing or spec'ing a unit for a specific project.
What Operators Need to Keep On File
MASH compliance isn't a one-time check at purchase. The documentation needs to travel with the unit through its service life:
- Manufacturer's MASH certification letter for the specific attenuator model and test level
- Test report reference (usually a Midwest Roadside Safety Facility or Texas A&M Transportation Institute report number) — an inspector can cross-reference it
- Configuration documentation if your unit's MASH compliance depends on specific mounting hardware, host vehicle class, or ballast weight
After an impact that requires component replacement, confirm that replacement components are OEM-specified and that substitutions don't void the manufacturer's compliance position. This is a more common problem than it appears: a well-intentioned repair using a non-OEM bracket or energy absorber can create a compliance gap that only surfaces when a project inspector asks for documentation.
For Texas-specific requirements, including TxDOT's CWZTCD List prequalification process and TxDOT's work-zone traffic control equipment eligibility, see Texas Traffic Control Equipment Requirements.
Talk to Us
If you have questions about MASH documentation for a unit you're running, or you're trying to determine whether a specific attenuator is compliant for an upcoming project, call us at (940) 600-5131 or reach out through our contact page.