NHTSA Grant of Petition for Rulemaking Rear impact guards Rear Impact Protection 49 CFR Part 571 Docket No. NHTSA 2014 0080
We need a new high speed rear guard standard, we need to require high speed guards on single-unit trucks.
The history of underride guard rulemakings gives us reason to be wary. The Clinton Administration during 85% public approval of stronger guard regulation passed a law that allowed a majority of trucks on the road to maintain their guards they were currently using built to weak TTMA (Truck and Trailer Manufacturer Association) recommendations. The TTMA has already commented that a majority of trucks and trailers already meet the diluted Canadian Standard. The Canadian Standard was weakened by a request from the TTMA that the standard must be harmonized to the weak American Standard to maintain compatibility of shipping between the U.S. and Canada. Years ago the Canadian Standard was an improvement, but technology moves along, current cars can withstand offset frontal impacts to 40 mph and car bumpers cost thousands of dollars. We need a modern Standard for trucks that is compatible with current car bumper technology including energy efficient size and weight and body material of future fleets, one that will serve us for 20 years or more. We will have to live or die with this Standard for decades.
Newer underride guard designs have the possibility to protect vehicles in higher speed crashes. Governments need to begin crash testing new designs and find those capable of better speed performance and determine the distance from the front and back of trucks or trailers to extend guards for improved high speed performance. Truck size and weight length limitations will need to be adjusted to accommodate the new guards length. “The size of an energy-absorbing truck front structure directly correlates to the survivable closing speed between car and truck in head-on collisions (e.g. 75 km/h survivable closing speed requires a 400 mm long energyabsorbing structure, 90 km/h, requires 800 mm).” From Volvo Report.
NHTSA in 1991 stated “Rear impacts involving underride, which are virtually all PCI (Passenger Compartment Intrusion), have the highest severe injury rate, from 2528 percent of all injuries sustained in rear end crashes. Without doubt, the great majority of these serious injuries occur above 30 mph, especially when one acknowledges the fact that two-thirds of all rear impact closing speeds are judged to exceed 30 mph. It is not surprising that severe injury production would be inordinately high in rear impacts by passenger cars given the statistical anomaly that over 50% of combination truck rear underride crashes by passenger vehicles occurred with big rigs that were stopped on the shoulders of high speed highways.” The current U.S. guard standards were acknowledged to be effective to 30 mph, a 40 mph standard was acknowledged to be feasible, but was overruled as not cost-effective due to a 40% higher cost for the stronger guards. Modern cars can withstand a 40 mph impact into a stiff wall but an impact with current U.S. underride guards above 25 mph can often be fatal.
NHTSA – Heavy-Vehicle Crash Data Collection And Analysis to Characterize Rear and Side Underride and Front Override in Fatal Truck Crashes: Impact speed estimation
“Impact speeds and relative speed of trucks and light vehicles at impact were estimated for 193 light vehicles that struck the rear of a truck in fatal crashes. The mean velocity of trucks at impact was estimated at 16.3 mph, but almost 41 percent were stopped at impact and 52 percent were estimated to be going 5 mph or less (including stopped). For striking vehicles, mean speed was 59.8 mph at impact, with a range of 15 mph to 110 mph. Relative velocity is more meaningful in terms of impact however. Overall, the mean relative velocity at impact was estimated at 44.0 mph. About 32 percent of the impacts occurred at relative velocities less than 35 mph, and in 43 percent, the relative velocity was 40 mph or less. However, many impacts were at very high relative velocities, and probably not survivable. In over 25 percent of the cases, relative velocity was over 55 mph and in 13 percent it was more than 60 mph.”
We clearly require an high speed standard of around 50 mph to save a majority of victims. We must not accept the Canadian Standard as it is only effective in all types of crashes to about 30mph and does not save most victims and it clearly is not adequate for 30 years of technology improvement and increasing energy efficiency. We are told to extend the front of the truck to handle high velocities of both the truck and colliding vehicle but clearly high speed impacts are the majority in rear impacts also.
Truckers properly placing triangles could prevent many of these crashes (it was reported many trucks were slow moving or stopped) likewise higher candlepower fluorescent tape colors could also prevent many rear end crashes. Driver reaction time is critical and increasing visibility of trucks provides this precious extra time to perceive and react to the danger ahead. Drivers have a right to this warning of slow or stopped obstructions of the roadway or shoulder.
Today we have the advantage of light weight high strength metal alloys, guards are no longer gas robbing heavy behemoths. We have 20 years of history of low guards not obstructing the trucks travel, railroad crossings have been redesigned as have many loading docks. We just need the space (long energy-absorbing structure) to decelerate the higher speed vehicles in crashes, we need to exempt trucks length restrictions to allow longer high speed guards, we can extend guards past the end of the truck or trailer and round the ends to deflect cars away from the truck in very high speed crashes. We need our government to promote the use of guards that exceed minimum standards, they must highlight lives saved and reduced costs such as insurance rates. The trucking industry have spent years railing against better guards, only the government has the funds to turn around drivers negative views of effective safety equipment. Using it does not make you a bad driver, using it makes you a caring driver.
The Canadian Standard was an improvement years ago, but it is not an high speed standard. It did not meet the crash test recommendations including outside end of guard bracing to increase strength that were made by George Rechnitzer and team at Monash University in the 1990’s.
This is 2014! We need an high speed standard to ultimately save millions of lives and serious injuries as other countries adopt the new standard. Guards are wonderful technology, they save everyone even errant drivers.
Crash test and recommendations at 75km/h (About 47mph) from MUARC in the 1990’s.
IIHS crash tests show Canadian Standard guards fail in 35 mph full offset crash tests, this is an standard good to about 30 mph which does not meet crash worthiness of modern cars which “absorb the energy of a 56 km/h full-width rigid wall impact and a 64 km/h deformable barrier crash with 40 percent overlap” as reported by IIHS. If we provide an energy absorbing guard we should at least expect a 47 mph standard to meet modern cars current crash worthiness. We need to expect the new guard standard to last about 20 years and it must match the crash worthiness levels of cars in future fleets.