Following and Stopping Distance

A reading of Delaware Law below clearly identifies “THERE ARE NO ABSOLUTES” for determining a legal following distance.

Motor Vehicles
Operation and Equipment

§ 4123. Following too closely.
(a) The driver of a vehicle shall not follow another vehicle more closely than is reasonable and prudent, having due regard for the speed of such vehicles and the traffic upon and the condition of the highway.

FACT: Stopping distance is a factor in determining following distance. Therefore, “Smart Defense” by the “The D Team” will identify a generally accepted formula to determine stopping distance.

Stopping Distance = Perception+Reaction+Braking Distance

Not much help is it? Then again maybe it can be helpful!

Can you imagine driving on a Delaware roadway at 45 miles per hour and being able to apply the above formula? First, one would have to know the braking distance for that particular vehicle traveling at 45 miles per hour. In order to determine the braking distance the driver would have to know the condition of the vehicle (weight/tires/shock absorbers & more). Then the weather including road traction and even the direction and speed of the wind would need to be determined and plugged into the formula. Unfortunately, there still would not be enough information available. The driver would then have to factor in the number of feet traveled for that individual’s reaction time — not good enough yet. Perception is the next factor in determining stopping distance. Perception is recognizing the need to stop. Perception will differ greatly depending on far too many variables to discuss. Unfortunately, your vehicle is no longer traveling at 45 miles per hour. You are now traveling at 55 miles per hour and it is raining. Start over or recognize “THERE ARE NO ABSOLUTES” when it comes to determining stopping distance.

However, let us not short change the information in the formula. Knowledge of the factors in the stopping distance formula Stopping Distance = Perception+Reaction+Braking Distance can help a conscientious driver make better decisions.

FOLLOWING DISTANCE: There are two theories that dominate following distance.

1. Counting the number of seconds your vehicle trails the vehicle directly in front of you.

The counting technique is to find an object down the road and begin counting seconds when the vehicle to your front reaches that object. The counting stops when your vehicle reaches the same object. If you reach the target object in a shorter time than your predetermined safe following distance (number of seconds), an adjustment should be made.

Some Major Flaws In Counting Seconds:

a) Since vehicle operators constantly change speed there would be a need to count following distance seconds continually throughout your driving experience.

b) There is no consistency when different individuals mentally count seconds. Thus the safe following distance would differ from individual to individual depending on their mental evaluation of the length of a second.

c) This counting technique at night becomes extremely difficult when a driver is attempting to find an object for a point to begin the counting process.

d) Counting seconds as a method to determine following distance can also be extremely distracting thus adding to the hazards of the driving process.

2. “Smart Defense” by the “The D Team” suggests the driver of a motor vehicle keep their eyes on the road. Check your speed and maintain a minimum of one car length (15-20 feet) for every 10 miles an hour you are traveling. This way the distance judgers are keeping their eyes on the road in front of them instead of searching for a yet to be
discovered counting point.

Of course, no matter which technique you choose there are other factors that must be taken into consideration such as weather/road surface/traffic/etc. which would require an increase in following distance — “THERE ARE NO ABSOLUTES”.

Delaware Defensive Driving Course