When an obstacle is in front of you on the road, you want to stop as quickly as possible. Your own reaction time determines how quickly you come to a stop, but several more factors come into play as well. To learn more, read this guide to factors that affect your stopping distance.
First, the condition of the surface on which you’re driving makes a big difference. Dry areas are conducive to easy driving and quick braking. On the other hand, wet or icy roads severely limit your stopping ability and greatly increase the total stopping distance.
Be aware—road conditions can also change suddenly as rain, snow, or ice develops with a drop in temperature. Even if precipitation has just started to fall, don’t presume that you can stop as quickly as you could 15 minutes ago.
Tire pressure and tread depth
The condition of your tires is a second factor that affects stopping distance. Tire pressure is part of this equation. Properly inflated tires ensure the shortest stopping distance. When you overinflate your tires, you decrease the surface area that contacts the road. As surface area decreases, the amount of friction on the road goes down as well. The result is an overall longer stopping distance as you brake.
Your tread depth falls on the other side of the equation. Over a tire’s life, the tread that grips the road gradually wears off. As it wears, the tire loses definition and with it the ability to grip the road and stop quickly, lengthening your stopping distance.
Shocks and struts condition
Your shocks and struts represent other structural factors that, should they deteriorate, affect your car’s performance and braking. In fact, an increased stopping distance is one of several signs of worn shocks and struts. When you press the brake pedal, healthy shocks and struts typically cushion the force of your car’s redistributed weight and make it still. When they wear down, your car throws its weight around unpredictably, making the braking process more varied so that it takes longer overall.