Breaking/stopping distances?!?

Question

What is the best way to work out stopping distances?

i.e A car traveling at 50mph on a good dry road, whats the safest stopping distance?

Answer 1

picking a stopping figure like 200 feet can be helpful, however, where you think 200 feet away is and where I think 200 feet is may be totally different.

When driving look at your speed and ask yourself, at this speed, if the guy in front slams his brakes on for some reason could I come to a safe stop or would I need to slam on my brakes too.

If the answer is the latter, your driving too close.

Answer 2

There is no way, regardless of what the Highway Code says. You can get guidance figures for thinking distance, but NOT breaking distance.

The tyres on your car, the condition they are in, the road surface-all affect breaking distance, see link below.

Answer 3

traveling at 50 mph

Thinking distance 50 feet

Braking distance 125 feet

Over all stopping distance 175 feet

Use the link on the sources its really helpful on this i used it for Science coursework.

Answer 4

An easy way to remember is this

20 mph x 1 = 20ft braking + 20 ft thinking = 40 ft

30 mph x 1.5 = 45 ft braking + 30 ft thinking = 75 ft

40 mph x 2 = 80 ft braking + 40 ft thinking = 120ft

50 mph x 2.5 = 125 ft braking + 50ft thinking = 175 ft

60 mph x 3 = 180 ft braking + 60 ft thinking = 240 ft

70 mph x 3.5 = 245 ft braking + 70 ft thinking = 315 ft

Answer 5

Determine the speed the car is traveling--the higher the speed, the greater the braking distance. For this example, a speed of 70 miles per hour will be used.

Establish the stopping distance. This is the distance from your car to the object in front of it. To estimate stopping distance when driving, remember that the average car length is 15 feet. So four car lengths is roughly equal to 60 feet. When driving 70 mph, the stopping distance is 102.7 feet per second (fps = 1.467 x mph).

Institute a deceleration rate. This is the rate that applying the brakes slows the vehicle. This rate is typically 20 feet per second.

Establish the stopping time. When traveling at 70 mph, which equals 102.7 feet per second if the deceleration rate is 20 fps, the stopping time equals 102.7/20 = 5.135 seconds.

Ascertain the thinking distance, which is reaction time as it relates to distance. Reaction time can take an average of 2 seconds to set in and realize that there is a problem. The reaction time can vary given the age of the driver, condition of the car, distraction in the vehicle and condition of the road. The formula to make a precise calculation 102.7 fps x 2 (reaction time in seconds) = 205.4.

Calculate the total braking distance. This formula is 1/2 the initial velocity in feet per second multiplied by the time required to stop, which is 0.5 x 102.7 x 5.135 = 263.68. The calculated thinking distance is 2 x 102.7 = 205.4. Add the two numbers together. 469.08 feet is the total braking distance.