Citation: I live on a fairly busy road in London, UK. I just watched 45 cars go past my living room window with only one person in, followed by a double decker bus with about 5 people in it. Hardly efficient!
You can try and make people feel guilty so they use mass transit or you can actually help it make their lives better. Which way do you think will be the most effective?
Bottom line: solve for time.
I work in a downtown business district. A recent office move and resident parking, constraints in parking facilities, and heavy enforcement of once-loose parking rules vaporized office worker parking. This affects 20-30k people.
Result: The telecommuting program participation rate is up, and people are taking public transit options, several of which are free to them.
The car problem in society is all about who bears the costs for things.
By making parking "free" to the end user, you make it easy for them to make choices around a car. Usually, public transit is cheaper than driving, but adds time. In my case, I can drive 15 minutes and pay $250/mo to park, take a bus for 25-30 minutes for $25/mo, or walk for 45-60 minutes for $0/mo.
Think about NYC and it's famous mass transit system. Why does that exist, where just 200 miles away, Boston is a sprawled out driving disaster? The root answer is that Manhattan is an island, and there is no parking. You cannot just bulldoze a hill to put a 50 acre Wal-Mart parking lot there.
Absolutely! People don't like to spend hours in a traffic jam, but if they do it every day it's just because they don't have a faster way to get to their destination. Yes, public transportation may be cheaper, but it is slower unless you live and work next to two stops of the same train/bus line. What is more important: time or money? Given the ever increasing road traffic, people clearly prefer time.
Yes, I understand that some people need big cars with poor fuel efficiency. (You need a 4x4 to get over the hills in winter; or for all the sports gear you're using; or because it's your business.) But people in the suburbs tootling around doing 40 mile commutes every day just need a comfortable car with good efficiency.
Cheap gas and complacency really hurt the US.
Even better, instead of cubicles, we could use an array of cameras and monitors to simulate shared working spaces. And instead of spending money on road/rail/air transport infrastructure, we spent it on high-speed data transfer links.
So I could have an office on a beach, that when I entered it, I was actually inside a shared, real-time space with my work colleagues.
Totally possible with current technology, but not with mindset or infrastructure constraints.
You will not curb the suburban sprawl problem in the US until ways develop for communities to control who lives in them. Right now the only mechanism is price. The rich can sustain unsprawled urban enclaves because they price undesirables out of their neighborhoods.