Absolutely untrue.

Stupidity causes this.

A freeway can handle every single vehicle at 45 mph that it currently handles at 5-10 mph. In fact, it can handle significantly more vehicles.

The problem, very simply, are the DB's and people who don't understand the ramification of hitting the brakes. They cause the accordion effect that will stop the traffic at that specific point for several hours.

You may notice, on rare occasions, that the traffic is very heavy but moving at 50 mph..........and does not stop. This is a very tenuous situation and it only takes one DB to upset the finely tuned system.

If the drivers were educated and not DB's, traffic problems would not exist.