Anyone out driving the day before Thanksgiving needs to be prepared for possible big traffic delays with traffic congestion predicted to be 25% worse than a typical Wednesday afternoon, according to the traffic analytics company Inrix.

According to the company’s annual Thanksgiving Traffic Forecast, the Wednesday pre-Thanksgiving rush hour is expected to begin two hours earlier than a typical Wednesday. Drivers trying to avoid the worst delays should avoid travelling between 2:00-5:00 p.m, according to Inrix

"Encouraged by low gas prices and a steady economy, travelers will experience more traffic on our roads than in recent years when more people stayed closer to home for the holiday," said Jim Bak, Inrix analyst. "While good news for businesses, drivers will battle more traffic heading out of town this year, particularly on routes near major airports."  

Top 10 Busiest Cities for Thanksgiving Traffic

Los Angeles, New York, Portland, and San Francisco top this year's list of worst traffic cities with trips out of town expected to take from 25% to 36% percent longer than a typical Wednesday afternoon. The chart below predicts the peak congestion period and extent of delays for the 10 worst cities.

"Our advice to drivers wanting to avoid the worst traffic is to leave by 2 p.m. or after 6 p.m. on Wednesday,” said Bak. “If it's possible to wait to leave until Thanksgiving morning, roads will be free and clear as long as you're not heading to the Macy's parade or a major shopping center to get a leg up on Black Friday."

The above chart shows, for example, the average trip in Los Angeles on the day before Thanksgiving is predicted to take drivers more than a third longer than usual. "Los Angeles is simply the worst place to be on the Wednesday before Thanksgiving," said Bak. "The combination of people arriving for the holiday with those leaving town and normal commuter traffic will result in steady traffic all day long."

Busiest Airport Routes

Traffic congestion this year is expected to be worst on key routes to and from major airports nationwide as travelers headed toward flights combine with car travelers to create bottlenecks at these locations, meaning delays for anyone delivering or picking up air freight.

Black Friday Forecast

Inrix also analyzed traffic levels around America's busiest shopping centers over the last three years to predict what drivers can expect travelling around these areas on Black Friday. It forecasts traffic congestion will peak between 1 p.m. and 5 p.m., advising shoppers to head out early to avoid the worst traffic delays and hassles finding parking at the mall.  

The following table tracks the Top 10 busiest U.S. shopping centers, the peak congestion hour and the percentage change over 2013.