4-6Control of a VehicleYou have three systems that make your vehicle go whereyou want it to go. They are the brakes, the steering andthe accelerator. All three systems have to do their workat the places where the tires meet the road.Sometimes, as when you’re driving on snow or ice, it’seasy to ask more of those control systems than the tiresand road can provide. That means you can lose controlof your vehicle. Also see “Traction Control System” inthe Index.BrakingBraking action involves perception time andreaction time.First, you have to decide to push on the brake pedal.That’s perception time. Then you have to bring up yourfoot and do it. That’s reaction time.Average reaction time is about 3/4 of a second. Butthat’s only an average. It might be less with one driverand as long as two or three seconds or more withanother. Age, physical condition, alertness, coordinationand eyesight all play a part. So do alcohol, drugs andfrustration. But even in 3/4 of a second, a vehiclemoving at 60 mph (100 km/h) travels 66 feet (20 m).That could be a lot of distance in an emergency, sokeeping enough space between your vehicle and othersis important.And, of course, actual stopping distances vary greatlywith the surface of the road (whether it’s pavement orgravel); the condition of the road (wet, dry, icy); tiretread; the condition of your brakes; the weight of thevehicle and the amount of brake force applied.
