Rush hour traffic is, in my humble opinion, the worst thing in the entire universe. Spending hours in the car desperately trying to get home after working a full day is someone's horrible idea of a joke. The environment suffers right along side us as we creep our way through commuter hell. All those idling cars really do a number on the air quality, too.
In addition, the gas isn't even really being used to its full potential. It's troublesome enough that we have to use CO2-emitting fuel to get around in our society, but it's ten times worse when we just waste that pricey gasoline sitting, going nowhere, in congested rush hour traffic.
A simple way to waste less gas while commuting is by checking your local traffic reports online. You'll be able to get up-to-the-minute information about your streets and avoid areas of ridiculous congestion and settle for less preposterous amounts of congestion. Traffic.com is a good place to find this information. You should be able to find local sources of this info as well.
You might have to drive a little out of your way in some cases, but a car in motion isn't as damaging as an idling car. It's also better for the car to not let it idle. You win twice, and hopefully a third time when you arrive sooner than usual.