Public transportation takes about 50-100% longer to get where you want, unless you are part of the "lucky" few that live next to a major station and works next to another major station. It also often costs about as much as it would cost in fuel costs -- yes, you can factor in the car costs, but those are sunk costs as living without a car is not an option anyway (I'm not gonna bring my shopping in the train for starters).
Public transportation is really an abysmal failure, especially on the cost aspect. Its supposed to achieve economy of scale, but in reality it can't even beat a car with two passengers (and often not even with one passenger). And that's ignoring the time aspect (time is money, especially my free time).
If you really want to solve these kinds of problems, I'd look beyond transportation, but more to the reason we transport ourselves: work. Make it so people can work from home or nearby reuseable offices.