Electronic Stability Control

I was recently teaching vehicle operations during a law enforcement in-service class, and I drew an icon on the whiteboard. I asked, "What does this icon mean when you see it on the dash of your cruiser?"

Out of the 13 students, no one knew what the icon (a vehicle with swerving lines beneath) meant. The icon (see image above) is a warning light that a driver has activated the vehicle's electronic stability control (ESC). When the operator sees this icon light up on the dash, it means the computer in the vehicle has detected a problem, usually some type of skid, and has deployed countermeasures to keep the vehicle going in the desired direction.

So how does ESC work? The National Highway Traffic Safety Administration (NHTSA) describes ESC as a system that applies the brakes electronically at varying rates to each wheel on the vehicle. This helps keep directional control of the car while the driver is having trouble controlling the vehicle and keeping it stable. A new study from NHTSA found that this technology is responsible for saving an increased number of lives each year since the federal standard changed in 2012 requiring it be installed in all new vehicles. All vehicles that weigh less than 10,000 pounds are now required to have this technology.

As a police instructor at the Kentucky Department of Criminal Justice Training (DOCJT), one of my main tasks is to teach vehicle operations to new recruits and veteran police officers. DOCJT used to have a wet track where we would practice skid control in the older Ford Crown Victorias. The two types of skids we practiced recovery on were the oversteer, where the rear end was skidding and coming around, and the understeer, where the front end was pushing or plowing due to the driver entering a curve under wet conditions with too much speed.

Since the academy has started purchasing newer cars with ESC, these drills are no longer necessary. Newer cars with ESC make it nearly impossible to get them to spin around, even on a wet track. As soon as a vehicle begins to lose traction in the rear, ESC takes over and immediately takes the torque away from the driver and applies braking to the tire.

It is necessary to show students how important it is to keep ESC activated. An easy way to get them to understand is to take a newer car on the wet track with ESC turned off, and immediately they will see the vehicle oversteer and spin around. Next, turn ESC back on, and students will be impressed that the vehicle does not spin out.

So why do manufacturers put an ESC button in a vehicle when it is such an important safety feature? ESC is the most important safety feature that has been put in a vehicle since the limited slip technology. During class, I stress to students that it should never be turned off because a driver will never be quick enough to do what this technology is designed to do. However, when a cruiser is stuck in the snow, and the vehicle will not spin, then one will have to reach down and turn it off to get unstuck, and then turn it back on.

Police officers need to remember that the laws of physics still apply. ESC is not a 100 percent solution to officer-involved crashes. We still need to check our tires for underinflation, drive carefully on slick roadways and obey the rules of the road. A large majority of crashes involving police vehicles stem from poor decisions by the driver.