17.2 Roadside Safety Hardware Crash Criteria
provides guidance for testing permanent and temporary highway safety features to assess safety performance of those features, replacing guidance defined in
. Guidance includes definitions of crash-test levels with specified vehicle, speed, and impact angle for each level.
Roadside hardware safety devices are categorized by Test Levels which define the impact conditions that the device is rated to withstand based on structural adequacy, occupant risk, and vehicle trajectory. The standard MASH 2016 vehicles for testing categories include a small car (2,420-lbs.) and a large pick-up (5,000-lbs). TL-2 is used for lowspeed roadways (45-mph or less); TL-3 is for high-speed roadways (50-mph or greater); TL-4 includes the TL-3 criteria, plus additional testing for a delivery-type truck (22,000-lbs). The primary difference between MASH and the earlier
criteria is the increase in size and height of the tested pickup truck to account for the change in vehicle fleet, and to better simulate an SUV. Other changes include the small car weight, and angle of impact.
17.2.1 MASH Background
The November 20, 2009 memorandum from David A. Nicol specified the
as the latest in roadside safety hardware criteria. This AASHTO manual supersedes
for the purposes of evaluating new safety hardware such as longitudinal barriers, transitions, end terminals, crash cushions, breakaway/yielding supports, truck mounted attenuators, and work zone traffic control devices. It sets guidelines for crash testing and evaluation criteria for assessing test results. The joint AASHTO/FHWA implementation plan stated that all highway safety hardware accepted under the criteria in
does not need to be retested to MASH criteria; may remain in place; and may continue to be manufactured and installed. However, all new hardware that is developed must be tested and evaluated according to MASH. Additional relevant memoranda are as follows:
- May 21, 2012, memorandum from Tony Furst on the subject of Roadside Safety Hardware - Federal-Aid Reimbursement Eligibility Process and related Frequently Asked Questions. The memo establishes that states can certify that roadside safety hardware has been tested by an accredited crash test laboratory and meets MASH criteria and can thus be eligible for reimbursement.
- January 7, 2016, memorandum from Thomas Everett on the subject of . The memo discusses the agreement between AASHTO and FHWA that requires all new installations of safety hardware on the NHS to be evaluated using the 2016 edition of MASH.
- The AASHTO/FHWA Joint Policy Resolution PR-1-23 effectively ended the 2016 AASHTO/FHWA Joint Implementation Agreement.
17.2.2 Current TxDOT MASH Implementation Timetable/Policy
As product manufacturers and developers have continued to develop MASH 2016 compliant products, the FHWA in coordination with AASHTO has allowed additional flexibility with respect to the implementation of MASH 2016 compliant products by the respective states. The following are the categories of Roadside Safety Hardware Products and current TxDOT policy:
- W-Beam barriers and cast-in-place concrete barriers- Effective 12/31/2017, for all new permanent installations and full replacements, all W-Beam Barriers and cast-in-place concrete barriers shall be MASH 2016 compliant for projects let after this date.
- Guardrail End Treatments (SGTs)- Effective Feb 28, 2018, all new permanent installations and full replacement SGTs must be MASH 2016 compliant regardless of project letting date.
- Cable barriers, cable barrier terminals, and crash cushions- In December 2019, the FHWA in collaboration with AASHTO provided updated guidance that allows the continued use of NCHRP 350 or MASH 2009 compliant devices for those categories of devices where a MASH 2016 alternative may not be available. The webpage provides standards (whether MASH 2016, MASH 2009, or NCHRP 350) that are available for use until further notice.
- Bridge rails, transitions, all other longitudinal barriers (including portable barriers installed permanently), all other terminals, sign supports, and all other breakaway devices- In December 2019, the FHWA in collaboration with AASHTO provided updated guidance that allows the continued use of NCHRP 350 or MASH 2009 compliant devices for categories of devices where a MASH 2016 alternative may not be available. Note that all current Bridge Railing Standards, and Mailbox Standards are MASH 2016 compliant.
- Temporary work zone devices (including portable barriers and waterfilled crash cushions)- Devices manufactured after 12/31/2019 are required to be MASH 2016 compliant. Such devices manufactured on or before 12/31/2019, and successfully tested to NCHRP 350 or MASH 2009, may continue to be used throughout their normal service lives. Note that certain temporary sign supports do not meet MASH 2016 criteria. Testing is ongoing with these products. Also, trailer-type work zone devices such as arrow boards, and electronic portable message signs are not MASH 2016 compliant, but FHWA has currently exempted these devices due to safety benefits offered by their use.
All the standards available on the respective TxDOT Division standards webpage are available for use until future notice. As additional MASH 2016 compliant items become available, the remaining
or MASH 2009 items will migrate off the lists of available standards and the Districts will continue to be notified accordingly. A list of all available MASH compliant roadside safety hardware items and associated memoranda are available on the
.
The repair and replacement policies of Roadside Safety Hardware are governed by TxDOT’s
and the applicable
.