It is illegal to drive in the state of Maryland.

Governor Bob Ehrlich has issued an executive order prohibiting all non-essential vehicles from state roads.

State police say the order will cover about a 12-hour period so state vehicles have the freedom to clear roadways and help people who need it without passenger cars in the way. Officials in Prince George's County says it will enforce the ban until four in the morning. It may be extended.

The governor says too many people are making discretionary trips, which is interfering with snow removal and emergency services.

There are no regular state police cruisers on the roads right now -- only four-wheel drive vehicles. Officials say 300 additional troopers have been called in from home to help people who are stuck on the roads.