A pretty good showing on another one of those "green lists".
Denver Business Journal
Where does Denver need improvement? In a word, traffic.
As you know, Denver's light rail system is set to become one of the nation's most extensive. The planning for this goes back about 20 years, so kudos to everyone in the region who recognized the problem in time to make a dent. Portland is one of the few cities with better mass transit than us, and it's #1 on the list.
Portland re-legalized ADU's a long time ago, and Denver is doing the same this summer if the new zoning code is approved.
Traffic is mostly a peak-period problem, so improvements can be made without widening highways (again).
If you are looking for a personal solution to this problem, sell your house in the suburbs ASAP and move to a transit adjacent neighborhood before prices get too high. Other options include telecommuting, bike commuting, and getting up early or coming home late.
Car sharing is growing: http://www.occasionalcar.com/
This is a great private sector solution that is much cheaper than owning your own car. Occasional Car has grown from two cars to eight in just over a year.
If you already live in a walkable neighborhood, you should check out this math:
1. Sell your car and save $300-$2000/month
2. Clean up and rent out your garage for $100/month. (An idea not really allowed by the new zoning code)
3. Join Occasional Car for about $50/month.
You're ahead by at least $350/month!