FHWA Grades Guardrail on a Curve

Last Friday the 13th was a very unlucky day for taxpayers – that was the day the Federal Highway Administration announced that we, the people, would continue to reimburse states that choose to install an energy-absorbing guardrail end terminal that has been maiming and killing us. That announcement was bundled in a package of technical papers designed to explain away the last of eight tests on the safety of the ET-Plus energy-absorbing guardrail.

On January 27, an assemblage of distinguished persons from Trinity Industries, the manufacturer of the ET-Plus, the FHWA, and the fourth estate gathered at the Southwest Research Institute test track in old San Antone to bear witness to exactly how the end-terminal has been failing in the field. The Geo Metro, with a dummy in the driver’s seat, thundered toward a guardrail end-terminal and struck it at a frontal offset. The rail began to ribbon out through the chute, until it got jammed and folded in half. The Metro rotated and was speared by the folded rail.  (Watch the video)

But what are you going to believe – a bunch of technical papers with tables, photos, charts, percentages and words like “occupant impact velocity values” or your own lyin’ eyes?

 Obviously, Trinity’s BFF prefers that you bury your head in its reports. So we did. And there, The Safety Record Blog found something even more amazing than the stark video record of a weaponized guardrail. The Safety Institute has written a long letter to FHWA Acting Administrator Gregory Nadeau outlining the technical trickery employed to pass an obvious FAIL.  

For those of you with no time to spare for a detailed takedown, here’s the Reader’s Digest version:

The mission of the FHWA was to somehow conclude that an ET-Plus energy-absorbing end terminal folding in half and spearing the vehicle really did pass the NCHRP Report 350 occupant risk criteria and that driving the door inward like the point of fang, which directly struck the dummy’s femur wouldn’t have seriously hurt anyone.


The NCHRP Report 350 Occupant Risk criterion states: “Detached elements, fragments, or other debris from the test article should not penetrate or show potential for penetrating the occupant compartment or present an undue hazard to other traffic, pedestrians, or personnel in a work zone. Deformations of, or intrusions into, the occupant compartment that could cause serious injuries should not be permitted.”

First order of business was finessing the English language. In English, “penetration” means: “the action or process of making a way through or into something.” In the FHWA lexicon, however, “penetration” only occurs if the process makes its way through something. In other words, a prostate examination doesn’t involve any penetration if the doctor wears latex gloves.  The photos, however, showed that the driver’s side door was pockmarked with holes on the exterior and interior, which the report called tears. In other words, the iceberg didn’t penetrate the Titantic – it just caused a little tearing.

The idea of potential penetration was not addressed.

The second order of business was to attack the serious injury issue. For this, the FHWA had to finesse the science. Since they didn’t instrument the dummy to truly measure the injury potential, they had to work it backwards, post-crash. With the aid of Dr. H. Clay Gabler, a respected scientist from Virginia Polytechnic Institute and State University, the FHWA used existing crash data sets and static intrusion measurements to show that a driver exposed to the crash conditions this test would have been unlikely to have been at risk of serious injury from the folded rail impact to the driver door.

Occupant compartment intrusion is at its greatest at the moment a vehicle strikes a narrow object. This is called dynamic intrusion. After the crash, the vehicle structure partially bounces back, so the amount of intrusion post-crash, called static intrusion, is significantly less. The video shows the door being driven inward so far that it pushed the steering wheel into the right side of the dash. This is a much bigger intrusion than the 6.75 inches the testers, the Southwest Research Institute, measured afterwards. By the way, according to the photos, the static intrusion appears to have been measured with the door open – another way to minimize the intrusion measurement. 

With its 6.75 inches in hand, the FHWA turned to the National Automotive Sampling System- Crashworthiness Data System (NASS-CDS) databases in an attempt to quantify the risk of a serious injury. Instead of sorting the data to consider injuries in similar type crashes – narrow object crashes – they diluted the population by looking broadly at a subsample of crashes with the same amount of intrusion, such as rollovers or vehicle-to-vehicle crashes. But narrow object crashes have a much higher potential for serious injury, because the crash force is concentrated at a focal point, instead of being broadly distributed.

One person who understands this very well is Dr. H. Clay Gabler. Dr. Gabler co-authored a wonderful 2013 technical paper, in which he used NASS-CDS data to specifically examine guardrail end-terminal side impact crashes. Yes, one can, if one cares to, sift NASS-CDS data for specific crash-types – including guardrail strikes. (That paper looked at crashes in which the side was the first impact, rather than the second impact, like that in the recent ET-Plus test failure.) When you look for what you are looking for, you may find something very different. For example, in Injury Risk Posed by Side Impact of Nontracking Vehicles into Guardrails, Dr. Gabler found:

Intrusion appears to be a major risk factor in guardrail-side crashes, particularly terminal crashes. Crashes directly involving the occupant compartment (SHL of passenger compartment) were far and away the most dangerous, accounting for only 3% of all nontracking guardrail-side crashes yet almost 40% of total injuries.


For terminal-side crashes, driver-side impacts had significantly greater risk of injury compared with passenger-side impacts. Side crashes involving an end terminal were substantially over represented in driver injuries. End terminal contact occurred in about 25% of all guardrail-side crashes but represented almost 70% of driver injuries.

As for where the occupant might have sustained injury, the FHWA took the opposite tack. Instead of looking broadly for potential injury to the head, torso, arm or upper leg, the analyzers only looked at possible injury to the lower leg. They went looking below the knee, even though Dr. Gabler noted that the dummy took a direct hit to the upper leg. In fact, in burst of candor, Dr. Gabler conceded in his analysis:

My conclusion is that the risk of serious injury cannot be discounted simply because the impact is to the legs.  An AIS 3 femur fracture could occur as a result of an impact to the upper legs and would be considered a serious injury.

That’s the formula – look for the wrong things in the wrong places, the wrong way – and Voila! You didn’t see what you saw. PASS!!!

The federal agency had long treated l’affaire Trinity as a nuisance. In 2012, when competitor Josh Harman made allegations of an undisclosed design change to the ET-Plus that caused it to fail in the field injuring and killing motorists, the FHWA took pains to soothe nervous state highway engineers. When Trinity finally admitted to the agency that it had in fact altered the design in 2005, but just forgot to mention it, the agency said: “That’s okay. Just give us your seven-year-old tests and we’ll call it even.” When the American Association of State Highway and Transportation Officials asked the FHWA to study ET-Plus field failures, the agency sternly reminded the group that it hadn’t made this a priority, so that would just have to wait.  When journalists asked questions, the FHWA passed off the kerfuffle as a dispute between business competitors.

The agency has had to exert itself a bit more forcefully in the wake of an October federal jury verdict which found that Trinity defrauded the government when it decided not to tell the FHWA about that design change, as required by federal regulations. But neither a finding of fraud, nor the revelations that Trinity failed to disclose the design change deliberately, as memorialized in emails in which company principals talk about it, nor a crash test in which the energy-absorbing end terminal did exactly what it is doing in the field, can deter the agency from ensuring no harm comes to itself or Trinity Industries.

Another branch of the U.S. Department of Transportation tried this. It didn’t end well.

The National Highway Traffic Safety Administration aggressively shilled for Toyota, hired experts and contorted science to show that Toyota Unintended Acceleration could only be caused by a confused old lady, a jammed floor mat or a sticky accelerator pedal. Toyota’s still profitable, but it became notorious as the first automaker to plead guilty to a criminal fraud charge and the plaintiff’s lawyers – not NHTSA — finally ripped the cover off the technical problem. Toyota is now settling death and injury cases. NHTSA’s reputation has been shattered and agency principals have taken regular beatings on the Hill and elsewhere, forcing them to finally make automakers do things

We are watching the FHWA hurtling to the same destination.