NHTSA Releases Findings on Toyota Prius Unintended Acceleration

By: Staff Writer

Wed April 27 2011


NHTSA (commonly pronounced Nit-sa) is the National Highway Transportation Safety Administration - and they look into all kinds of issues related our safety on the nation's roads. This time last year, the buzz was all about Toyota and specifically about unintended acceleration in the 2010 Prius hybrid - the poor publicity from this controversy and related quality issues cost Toyota thousands of sales and likely millions of dollars.

A similar controversy back in the 1980s set Audi back on its heels in that decade - and a reputation for poor quality and unsafe vehicles takes years to overcome.

Well, NHTSA got together with a bunch of scientists and engineers from NASA to look into the Prius problem in particular and the Toyota unintended acceleration problem in general, and the results are both interesting and educational.

Toyotas, like many modern cars, control the car's acceleration electronically. That means that when you "step on the gas" you're simply telling the car's computer to accelerate, but the actual opening of the car's throttle and fuel delivery system is computer-controlled. The engineers from NASA went over the programming, the actuation mechanisms, the brakes, and perhaps most importantly the onboard data records from the cars that were reported to have the problem.

The result is that with the exception of one car that got the floor mat stuck on the gas pedal and some non-crash incidences of "sticky" pedals, every case of unintended acceleration was the result of "pedal misapplication" by the driver - in other words, the drivers were standing on the gas when they thought they were using the brake!

The executive summary of the report takes a page or two to deliver this finding, but the bottom line is that cars today have never been safer or better-engineered. The report suggests more work to make cars foolproof, but the bottom line is that there's no substitute for a good driver.

Interestingly, one thing NHTSA did NOT recommend was eliminating floor mats. Although it seems obvious that the modern style of floor mat that is hooked or screwed into the floor is a much safer design than just tossing a mat under your feet.

Oh and incidentally, remember we mentioned the Audi problem in the 1980s? The NHTSA report from that controversy found the same thing - it was the drivers, not the cars, that had the problem.

You can see the whole web page for the study here.