Jan. 5—This weekend’s winter storm is expected to create slippery roads and potentially treacherous travel conditions, and that has prompted PennDOT to issue restrictions on eastern Pennsylvania highways.

Starting at 2 p.m. Saturday, Tier 1 restrictions on some tractor-trailers and other vehicles will go into effect on the following highways:

— Pa. Turnpike Northeast Extension (I-476): Lehigh Valley (Exit 56) to Clarks Summit (Exit 130).

— I-78: entire length

— I-81: from I-78 to New York

— I-80: from Exit 173 (Lamar) to New Jersey

— I-84: entire length

— I-180: entire length

— I-380: entire length

— Route 33: entire length

— U.S. 22: from I-78 to New Jersey

Under Tier 1 restrictions, the following vehicles are prohibited:

— Tractors without trailers

— Tractors towing unloaded or lightly loaded enclosed trailers, open trailers or tank trailers

— Tractors towing unloaded or lightly loaded tandem trailers

— Enclosed unloaded or lightly loaded cargo delivery trucks and box trucks

— Passenger vehicles towing trailers

— Recreational vehicles and motorhomes

— School buses, commercial buses and motor coaches

— Motorcycles

Additional Tier 3 restrictions will take effect at 4 p.m. on these highways in northeastern Pennsylvania, which is expected to see heavier snowfall:

— I-81 from I-80 to New York

— I-84 entire length

— I-380 entire length

Under Tier 3 restrictions, all commercial vehicles are prohibited except for loaded single trailers with chains or approved alternate traction devices, as well as all the vehicles prohibited under Tier 1 and 2 restrictions.

PennDOT and the Pennsylvania Turnpike Commission will also implement speed limit restrictions on all vehicles during the storm, which is expected to continue through Sunday afternoon and evening. While only certain vehicles are prohibited, PennDOT is advising all motorists to avoid unnecessary travel.

Both PennDOT and turnpike crews were treating roadways ahead of the storm, according to PennDOT spokesperson Sean Brown.

PennDOT reminds motorists who have to travel during the storm to use extra caution, particularly on bridges and highway ramps, and to be on the lookout for black ice.