Subject: Question about traffic flow

I recently went on a trip with my family and we came upon a pretty severe 
traffic jam.  We finally came to the cause of the backup, a stalled car on the 
side of the road.  This car was not blocking traffic in any way.  As soon as we 
passed the stalled car, traffic quickly picked up to normal highway speed.  I 
would like to know why this occurs and if there are any mathematical models 
used to predict traffic flow.

Re: Question about traffic flow