If you look at any technical resource related to highway operations and roadway capacity, the conventional wisdom is that a roadway lane with no interruptions or impediments (driveways or traffic signals, for example) will handle 2,000 passenger cars per hour at its design speed. That doesn't vary by speed, either. Motorists traveling at higher speeds will tend to drive far apart, while those at low speeds will travel close together. The effective operating capacity is still the same: about 2,000 passenger cars per hour.
Transportation officials in some cities like New York City and Los Angeles will say they get higher numbers -- like 2,100 or 2,200 -- because people tend to travel closer together in those crazy urban environments.
None of this is a good sign, folks. Your basic rule of thumb for driving is to follow the "two-second rule" -- i.e., you should always leave at least two seconds of reaction time between yourself and the vehicle in front of you under normal conditions.
The two-second rule translates to a roadway lane capacity of 1,800 passenger cars per hour, not 2,000+ ...
- There are 60 seconds in a minute, and 60 minutes in an hour
- 60 seconds x 60 minutes = 3,600 seconds per hour
- 3,600 per hour x 0.5 vehicles per second (i.e., one vehicle every two seconds) = 1,800 vehicles per hour
FOLLOW THAT TWO-SECOND RULE, FOLKS!!
[The two-second rule translates to a roadway lane capacity of 1,800 passenger cars per hour, not 2,000+ ...]