MAP-21, the Moving Ahead for Progress in the 21st Century Act (P.L. 112-141), was signed into law by President Obama on July 6, 2012. Funding surface transportation programs at over $105 billion for fiscal years 2013 and 2014, MAP-21 was the first highway authorization enacted since 2005.

National Cooperative Highway Research Program (NCHRP) , Procedures for the Safety Performance Evaluation of Highway Features. Provides guidance for testing highway features to assess safety performance of those features, replacing guidance defined in NCHRP Report 230. Guidance includes definitions of crash-test levels with specified vehicle, speed, and impact angle for each level.

May 30, 1997, memorandum from Dwight Horne on the subject of " " identifies 68 crash-tested bridge rails, consolidating earlier listings and establishing tentative equivalency ratings that relate previous testing to NCHRP Report 350 test levels. Ten of the 68 crashtested rails were developed and tested in Texas.

August 28, 1998, memorandum from Henry Rentz on the subject of “ ” (with attachments). Extends implementation dates and adds caveats for use of safety hardware in new installations and 3R projects. Explicitly assigns responsibility to transportation agencies for defining "...when extensions, relocation, adjustments or major repairs to a feature constitute a new installation" and whether "...features that meet the acceptance requirements recommended in NCHRP Report 230...may remain in place."

May 16, 2000, memorandum from Frederick Wright on the subject of "Bridge Rail Analysis." Allows responsible transportation agencies to request FHWA acceptance of a specific bridge railing type that has not been crash tested based on analysis showing its similarity to a design that has been crashtested and found compliant with NCHRP-350 requirements.