eli5: would adding more lanes to a freeway/busy street really ease congestion or would you still get bottlenecks?

Question

I mean theoretically adding a lane or two should allow more cars to flow through, or would bad drivers still cause bottlenecks/gridlock despite the added capacity?

In: 28

Answer 1

Paradoxically adding lanes has a neutral effect on traffic at best. See adding a lane creates “induced demand” where by increases the supply of something, in this case easy/speedy travel, you increase demand. Basically because you increase the amount of cars a road can handle without becoming congested, that means more people will take that route leading to equal congestion.