The Case for Following Distance - Everywhere
Whether on the road in a vehicle, in a line at the ATM, or in the middle of a mosh pit, people exercise the ability to move or not move in unpredictable ways. The reasoning for an individual's specific behavior is often mysterious to those around him or her. But I assure you, it makes sense to him or her (or you, or me).
In the context of a mosh pit, personal space is not highly regarded. In contrast, prior to moving from the line to the ATM, many people perform a slight backward glance like a pitcher holding a runner on second base, to make sure that the zone of the ATM user is not violated by the encroaching mob. Traffic has far too many variations on this theme of territory to describe, so I'll use a mechanical model instead.
Think of a shock absorber. The basic parameters that are important to the function of a shock absorber are travel, resistance, and damping. For a whole car, these factors translate roughly into following distance, brakes, and recovering acceleration. If a shock has "long travel," the ride is smooththe shock has wide latitude in correcting the situation in a timely fashion. Higher resistance helps to provide quick recovery from bumps but at a comfort penalty. Damping helps to balance the resistance by slowing the recovery.
This translates well to the vehicle situation. If you maintain even a car length or two between your car and the one in front of you, the car in front can speed up or slow down briefly for whatever reason without so much as a notice by the driver behind. But as soon as any driver draws so close to the car in front that braking is required, a chain reaction is set off throughout the cars following. By providing a gapeven a small oneadjustments can be made and changes accommodated without the use of brakes.
Likewise, if you let the person coming off the ramp merge into trafficinstead of racing up to cut them offtraffic can continue to move smoothly. It's better to keep going 45 mph with a new person in front of you than to contribute to traffic moving at 15 mph. Eight feet of car length is a small distance to trade in exchange for an extra 30 miles per hour of speed.
For those who scoff and suggest that until your neighbors learn to act in kind my analysis is worthless, I give you two thoughts: a) lead by example; b) driving this way will lengthen your life and reduce your stress. I ought to know.