Where I live [Dallas/Fort Worth Metroplex], it's difficult to go 'car light' and damn near impossible to go 'car free'.
This area is just too spread out and it's not uncommon for people here to have a 50+ mile round trip to work and back. Also, the light rail system just isn't there yet. It's improving, but you need to live and work in some pretty specific areas to make a bike/transit commute work.

There was a time when I was working in downtown Dallas that I was able to make 'car light' work, but that only lasted about 9 months until I had to go into a more remote site, at which point it bike/train commute would have been +2 hours and 2 train changes each way.