Once the snow emergency plan is in effect, Maryland law requires drivers to operate vehicles equipped with snow tires as designated by the manufacturer or equipped with chains, according to the state police. Studded tires are allowed from Nov. 1 through March 31. During a snow emergency, vehicles cannot be parked on snow emergency routes.

The NWS predicted snow, freezing drizzle and sleet in the Frederick area Saturday during the daytime and icy roads overnight. Less than half an inch of snow and sleet accumulation was expected, with less than one-tenth of an inch of ice possible. Freezing drizzle, patchy fog and possibly sleet were predicted for Saturday night. There is a slight chance of rain Sunday night.

Maryland State Police snow emergency routes include:

U.S. Route 15

U.S. Route 15 (Business)

U.S. Route 40

U.S. Route 40 (Alternate)

U.S. Route 340

Md. Route 17

Md. Route 26

Md. Route 27

Md. Route 28

Md. Route 31

Md. Route 75

Md. Route 76

Md. Route 79

Md. Route 80

Md. Route 85

Md. Route 140

Md. Route 144FA

Md. Route 180

Md. Route 194

Interstate 70

Interstate 270