Thanksgiving travelers crowded airports, bus and train stations and highways Wednesday, putting up with tight security and bad weather that included heavy snow in the Midwest, rain in the Northeast and tornadoes in the South.

According to a survey conducted for AAA by the Travel Industry Association of America, 30.6 million people, or 3 percent more than in 2003, were expected to hit the road during the holiday weekend, even with gasoline prices nearly one-third higher than a year ago. An additional 6.6 million were likely to travel by plane, train or bus.

Highways were bumper-to-bumper in Georgia as drivers faced thunderstorms and a threat of tornadoes, part of a system that killed four people elsewhere in the South.

“We’re seeing some hectic and chaotic driving situations — the road rage, the rear endings, people not allowing other motorists to change lanes,” said Georgia State Patrol Trooper Larry Schnall. “We feel weather is playing a big role in it.”

At the Atlanta airport, many flights were delayed and a few were diverted because of the severe weather in the region.

Security was visibly tighter at Washington’s Reagan National Airport and lines snaked two-thirds of the way down the main concourse.

In Chicago, the first snow of the season caused delays up to three hours at O’Hare International Airport and some flight cancelations.

Six inches of snow was possible in the Chicago area as a second storm streamed into the region from the Plains. By mid-afternoon, snow had fallen from Michigan into Kansas, with more than 7 inches of snow outside Kansas City.

The weather also was disrupting travel in the Northeast. Airports in New York City, Boston and Newark, N.J., were experiencing delays up to two hours because of rain.

Meanwhile, drivers cruised through Pennsylvania Turnpike toll plazas for free Wednesday. Toll collectors and maintenance workers went on strike hours before the holiday rush.