# What human factors play part in traffic congestion?

Traffic congestion is a daily phenomenon that costs people a lot of time, is bad for the environment and may even cost some money. There are many obvious causes for traffic congestion, such as the amount of cars, size of the road, situational factors on the road such as accidents etc.(e.g. this blog or (Wiki).

It seems that increasing the capacity of the road capacity is not a solution to the problem, since it only appears to attract more users (Arnott and Small, 1994). Therefore, I was thinking whether there were any other factors that could influence congestion. It is obvious that each car has a human drive (well almost each car). Perhaps, their behavior could likely also play part in causing congestion.

Is there any scientific evidence that behavioral factors (e.g. excessive de- and acceleration or lane switching) may promote/prevent traffic congestion?

## References

Arnott, R., & Small, K. (1994). The economics of traffic congestion. American scientist, 446-455.

• One similarity is to production line mentality in a factory. The production works optimally only when all operations occur at the expected/planned speed. In traffic, a primary improvement would be if all vehicles traveled at the same speed with a fixed distance between them. This may be possible on a single lane road with no entrance or exit, but this is unlikely in most environments where traffic is heavy enough to cause a concern. – user3169 May 11 '17 at 5:12
• @user3169, welcome at CogSci and thanks for the response. If you have any references to that you are welcome to formulate an answer, and I'll be happy to give you an upvote :) – Robin Kramer May 11 '17 at 5:26

The IDM acceleration is a continuous function incorporating different driving modes for all velocities in freeway traffic as well as city traffic. Besides the distance to the leading vehicle s and the actual speed v, the IDM also takes into account velocity differences ∆v, which play an essential stabilizing role in real traffic, especially when approaching traffic jams and avoiding rear-end collisions (see Fig. 3). The IDM acceleration function is given by: