Ask HN: How can tech improve traffic

If you're like me you hate traffic and love solving problems.

Today I hit exactly 23 red lights on the way home from work. We all know as population grows, so will the issue of rush hour and miserable red lights. So it got me wondering, How can technology improve traffic and transportation? What company's are currently working on this issue?

This isn't to steal ideas, I just want to get your hacker brains flowing and possibly solve a problem.