What causes traffic on the freeway?

-When a road is running at or near its full capacity, there will be a long line of cars close together. If someone brakes - it could be because someone else changed lane, there could be something in the road or the driver could just be correcting a slight error of theirs - the car behind will have to brake slightly harder (if he doesn't, he'll crash). The person behind him will have to brake a little harder too, and it keeps going on until eventually people are braking so hard that they're stationary for increasing amounts of time, and that's how your queue forms. It'll keep getting worse until eventually there is no car following behind, which on a busy road could take hours.



That is the cause of almost all traffic jams, as anything you can imagine (an accident, a busy merge) causes people to brake. The only other cause is when more people are trying to use a road at the same time than it can handle, for example if a lane was closed for roadworks or if the road was just sub-standard. This is quite similar because the queue forms as people have to slow down to filter in effectively.Lotsa people going different directions at the same time. Also lousy traffic light timing makes congestion worse.

About once a month I will catch green lights all the way home or to work. Every other time I might catch 1 green light. Some days I can't catch a green light to save my...
People driving cars there. Just think, if everyone stayed off the freeway, there wouldn't be any traffic. DUH!
Slow People

Geezers

Accidents
Cars, driven buy unskilled morons. And lots of 'em.
A car crash or if there's a state trooper near.
drivers.