A travel advisory remains in effect for all state, US and interstate highways, and the Alabama Department of Transportation continues to advise people to avoid driving until conditions improve, according to a press release sent out at 11 p.m. Tuesday.

ALDOT crews are working around the clock to treat roads and bridges with priority to mainline interstates in an effort to keep them open or clear back-ups. Some areas remain impassable on the state system, including locations around the Birmingham area.

Icy conditions will remain in effect for much of the next 24 to 36 hours, making travel hazardous.

The ALDOT Emergency Call Center closed from midnight to 6 a.m. Wednesday. Live operators resumed providing travel-related and road condition information at 6 a.m.

Upgrades have been made to the ALDOT Web site to improve public access to real-time road conditions from around the state. For the latest information on road closures and conditions on state, U.S. and interstate highways, go to www.dot.state.al.us.