[lunarhighway]

that's not to good, because it means your winter milage is even worse than than it would appear. especially since i imagine spinning the wheels freely on ice takes less energy than travle the actual distance.

another way to check any anomalies is to use the trip odometer and compare identical routes like you're commute with snow and no snow. also google maps can give you a fairly accurate guess on how long your actuall route is.