Any form of coercion will backfire in regards to improving the transportation system. Anything run by a public bureaucracy is inefficient and costly. People will figure out their own ways to get around town without the help of a centralized government. There is one exception in that the government can help move things along by offering financial incentives for people to use more efficient and earth friendly forms of transportation. This is already happening with the tax rebates offered to owners of hybrid vehicles.
Furthermore, there can be financial incentives for people to carpool. People behave on their own self interests. Offer someone a reward for certain behavior and they will be more likely to comply. Try to force someone to behave through force and they will naturally resist.
In fact, there should be no government run transportation system, it should all be privatized. Now if we are discussing the use of private busing systems then we can make headway. I believe the people will use these forms of public transportation if the buses are more luxuriously equipped. People want to feel comfortable. Increase the comfort level and you will increase rideshare.
Also, people should be given financial incentives for using bicycles instead of cars. I see more people using bicycles and compact forms of transportation as more and more cities become metropolitan like New York City. We will reach a point where there will simply be very little room for efficient automobile movement. People will resort to taking monorails or they will simply walk if at all practical. Forcing people to use public transportation will not solve problems but create more of them.
Interestingly, I’ve noticed that when gas prices go up there are less people on the road. One way to reduce undue traffic is to raise the cost of driving. This includes creating more toll roads. Again, this will pressure people to carpool or to travel only when necessary. Using privately funded total roads will also improve traffic flow without costs to the taxpayers.
Demographic growth and traffic planning go hand-in-hand. In order to reduce traffic loads in certain areas there will have to be government imposed laws against urban sprawl. Reducing population densities will help reduce traffic jams in their respective areas. Improving transportation is something that everyone can participate in. Creating a culture where carpooling, telecommuting, and environmentally friendly transportation is valued is a step in the right direction.