Severe congestion is already frequent on 40 percent of California's highways. If current trends continue, by 2010 almost half of all travel will be under congested conditions. The average freeway speed in major urban areas will be reduced to 11 miles per hour.
Fuel consumption increases dramatically at such low speeds.
A decrease from 30 to 10 miles per hour increases fuel consumption by 100 percent. Other states in the Northeast are looking to adopt California's mandate.