So, I live in one of the great traffic nightmares of the world, Atlanta. We have a freeway downtown that is 8 lanes each way, and they are almost always full.
There is a bypass around the city that has become a main thoroughfare for a lot of people going to work. It's now stopped solid from about 8am till 9:30am in all directions.
Our side streets are just as bad. The cities and counties have a "zero growth" policy, to stem the sprawl. So, the governments do not have infrastructure improvement plans. But, the growth continues because developers by the hundred get variances to build their new subdivisions or commercial developments.
I've been thinking a lot about how to make things better and there are probably a few pretty simple things that would help:
Get rid of the stupid "High Occupancy Vehicle" lanes. They only restrict traffic flow, have no impact on car pooling and give police about 500 additional people to pull over every day for using the lane with only one person in the car.
Make the freeway dividers 8 to 10 feet high so traffic on the other side can't see an accident.
Divide the freeways into local and express lanes. If we could segregate the traffic into local and express, we'd see a lot better lane usage. Right now, I can be 6 lanes over and have to cut all the way over to get an exit. and because I'm bad at planning, I wait till the last minute to do so, and slow everything down as I try to make my way over.
Get rid of the zero growth policies, and tie infrastructure improvements to actual population growth, not planned growth.
Atlanta also has a bad smog problem. We are constantly bombarded by ads from the governor asking people to carpool or telecommute. We have a big push to use more fuel efficient cars. Those aren't the answer. The answer is to deal with the traffic problem. We have about 1 million cars sitting on the freeways idling for 20 minutes to an hour EVERY morning and EVERY afternoon. If you want to impact the pollution problems, that's how you do it.