Imagine for a moment, that you are driving down the road and you go to press the brake pedal, but as you do, you unintentionally press the accelerator pedal as well, what do you think would happen?

In modern computer controlled vehicles, there is supposed to be a brake override function, where if the car detects the brake and accelerator pedal being depressed at the same time, the signal from the accelerator pedal is ignored and the brakes are left to apply. There is also those who suggest the brake force being applied is always sufficient to overcome the acceleration of a vehicle.

That didn’t happen in the Bookout/Schwarz case. In 2005 Jean Bookout was driving their Toyota Camry. During that journey they collided with and killed Barbara Schwarz. Bookout claimed the vehicle had suffered a sudden unintended acceleration. Following this Bookout and the family of Schwarz sued Toyota citing defects with the vehicle.

Counsel for Toyota argued there was no defect with the Toyota vehicles or it’s software and that this was simply a case where Ms Bookout had mistakenly pressed the accelerator instead of the brake, however, experts for the claimants found evidence to the contrary, specifically 150 feet worth of skids marks, indicating the brake pedal was being depressed. The jury in the trial found in favour of Bookout and Schwarz, indicating they thought there was more likely a defect with the Toyota which led to the death of Schwarz.

So what happened? Well, if you have a spare 60 minutes, I would seriously consider watching a presentation of the case study provided by Professor Phil Koopman (https://www.youtube.com/watch?v=DKHa7rxkvK8&t=1425s ) who was one of the experts in the case for the Bookout/Schwarz.

According to many, the brake override function should work and the brakes should be physically capable of overcoming the cars acceleration, but in this 60 minute presentation, Professor Koopman methodically sets out why that may not always be true and why it was not true in the collision resulting in the death of Barabara Schwarz.

The presentation also perfectly illustrates why even where a brake override function is present in a car, it may not always work as you would expect as in some systems, the example cited is where a driver already has their foot on the brake pedal.

In this example, where a driver already has the brake pedal applied, if they were to depress the accelerator, the brake override function would not activate, because the system is waiting to see the drivers foot come completely off the brake pedal.

In other words, if you brake, depress the accelerator, there is still a possibility the car will accelerate, because it hasn’t seen you take your foot completely off the brake.

The presentation also highlights issue around brake servo vacuum and its depletion in acceleration events, which may increase the force required by a driver to apply the brakes.

If you are presented with a sudden unintended acceleration case, there may come a point where you have seek additional expertise to truly determine whether a vehicle has suffered one or not and if so, the cause of it.

The link to Professor Koopmans presentation:

https://www.youtube.com/watch?v=DKHa7rxkvK8&t=1425s

The link to a summary of Bookout/Schwarz case courtesy of Beasley Allen Law Firm:

https://www.beasleyallen.com/article/toyota-sudden-unintended-acceleration-lawsuit-ends-in-landmark-verdict/