Police and state transportation departments report heavy congestion Wednesday afternoon on interstate highways in the Charlotte region and in several other major metropolitan areas across the Southeast, on what is traditionally one of the busiest days of the year on regional roadways.

The next several hours -- until about 9 p.m. -- are expected to be the worst for holiday travelers.

Beautiful weather and dropping gasoline prices are greeting the hundreds of thousands of Carolinas residents who are hitting the road today for Thanksgiving trips.

At 3:30 p.m. Wednesday, the N.C. Department of Transportation was reporting heavy congestion slowing traffic to about 30 mph on both northbound Interstate 77, from Huntersville to Mooresville, and on northbound Interstate 85, from the University City area up to Concord.

Very slow traffic also was reported on both sides of I-485 in southern Mecklenburg County, and on I-77 northbound in Iredell County and I-85 southbound in Rowan and Cabarrus counties.

Heavy congestion also was reported near Columbia; in Richmond and around the District of Columbia; and in the Atlanta area (see details at end of this story). Slowdowns also were being seen on portions of I-81 in central Virginia.

More than 1.5 million people in the two states will travel 50 or more miles by motor vehicle for the holiday, and those who left early Wednesday morning found little or no problems on the roadways.

“This is the only time to travel,” Karl Parker, of Gaffney, S.C., said about 5:15 a.m. Wednesday as he fueled his Ford Escape at a convenience store on Providence Road near Interstate 485.

Parker said he and his family -- a wife and two children -- were headed for northern Virginia.

“I’ve experimented with times to come through Charlotte, and this works out best on the day before Thanksgiving,” he said. “On the day before Thanksgiving, it’s all about avoiding the hassles.”

The hassles include heavy traffic volume, and the number of motorists on interstate and other major highways will build later in the day.

AAA Carolinas says 45 percent of Thanksgiving travelers will be on the road Wednesday. The next-biggest day is Sunday, when 36 percent return home.

Those motorists are finding gasoline prices lower than last Thanksgiving. The average price in North Carolina is $3.30, which is about 6 cents below levels of Thanksgiving 2011. Charlotte’s prices are around $3.25.

Prices are even lower in neighboring South Carolina ($3.13), Virginia ($3.23) and Tennessee ($3.16).

The weather is no problem across the eastern United States. Sunny to partly cloudy conditions are forecast Wednesday, and after a chilly start, temperatures are predicted to be above the seasonal averages. High temperatures in Charlotte will approach the mid 60s Wednesday afternoon.

Good weather also is forecast for other major destinations of Carolinas residents -- the beach, the mountains, Atlanta, Florida, Washington, New York, and Philadelphia.

Police will be highly visible on roadways, however.

State police in North Carolina, South Carolina, Georgia and Virginia say they have extra patrols on duty this weekend. The N.C. Highway Patrol says troopers will be watching for motorists who are not wearing seat belts or are speeding. A similar crackdown is planned in South Carolina.

Here is a list of interstate conditions in Southeast states:

NORTH CAROLINA ... I-77 northbound is congested from Huntersville to Mooresville. Average speeds are 20 to 30 mph. Another congestion area is around Statesville.

I-77 southbound is congested in the Mooresville area, with average speeds of 25 mph. Even heavier congestion is slowing traffic to 20 mph in south Charlotte.

I-85 northbound is congested from mile marker 43 to mile marker 55, from University City up to near Concord Mills.

I-85 southbound is congested (20-30 mph) through Rowan and Cabarrus counties.

Also, I-95 is slow near the North Carolina-Virginia border, also due to congestion.

SOUTH CAROLINA ... Heavy congestion on I-20 both eastbound and westbound near Columbia.

Heavy congestion on northbound I-26 near Greenville.

Heavy congestion at several spots on northbound and southbound I-95, especially near Florence and near I-26.

I-85 southbound near Spartanburg is very slow, with a pair of collisions clogging traffic.

VIRGINIA ... No problems on I-77.

Congestion is reported near Roanoke and near Harrisonburg on northbound I-81.

Plenty of problems on I-95. Heavy congestion reported near Richmond. Heavy congestion (6 miles of backups) reported north of Fredericksburg, around mile marker 140. And a collision still slowing traffic on northbound side, between Richmond and Fredericksburg near mile marker 104. Slowdowns stretch about 3 miles.

TENNESSEE ... Heavy congestion on I-24 westbound near Chattanooga.

A crash is blocking lanes on I-75 northbound near Chattanooga.

GEORGIA ... Heavy congestion slowing traffic to 25-30 mph on I-85 and I-75 near Atlanta.

MARYLAND ... Heavy congestion on all interstate highways in Prince George’s and Montgomery counties.

Wreck on I-270 northbound in Frederick County. Right 2 lanes closed. Slowdowns for about 2 miles.

WEST VIRGINIA ... no problems. No major congestion.