Incentives should be available for pushing work from home/telecommuting. There are many office jobs where it could be possible, but the big draw back there is security and cost. Some companies don't want to invest in the infrastructure to support that many more telecommuters.
Varying shift hours would be another great way, but as others mentioned, it can really mess things up. Personally, I work 7-4 instead of 8-5. The difference in commuting? About 50% travel time. IE - The closer I leave to 8, it gets closer to 45 minutes than the current 30 minutes. In bigger cities, I am sure that is much, much worse.
It's definitely a tricky thing to deal with, but the single biggest problem is the 8-5 work day that 80% of people seem to have. If you could blend that to some 6-3, some 7-4, some 8-5, some 9-6, and some 10-7, you'd nearly completely minimize "rush hour." But, there is no simple way to make sure this happens, and it can have adverse affects in terms of B2B communication.