TUCALOOSA, Ala. (AP) — The three days leading up to Thanksgiving are the most dangerous time to be on the road, according to a recent University of Alabama study.

Alabama’s Center for Advanced Public Safety found that there was a daily average of 460 crashes on the Monday, Tuesday and Wednesday before Thanksgiving in 2015. The daily average for the rest of the year is 409.

The number of crashes could go up this year, as experts predict the highest number of Thanksgiving travelers since 2007.

AAA projects that 48.7 million Americans will travel 50 miles or more from home this Thanksgiving, an increase of one million travelers compared with last year. That’s a 1.9 percent increase over 2015 and the most expected travelers over the past nine years.

The increase in travel this year is spurred by improvements to the economy during the second half of the year, according to AAA, increased consumer spending and overall strength in consumer confidence. Gas prices are holding at close to $2 per gallon, the second-cheapest in nearly a decade, according to AAA.

More traffic, traveling after sunset, deer and alcohol consumption all play a factor in the increased number of crashes, according to the UA study.

“The weekdays immediately preceding Thanksgiving have significantly more crashes than would be expected from the average of the rest of the year,” said David Brown of the university center. “These are days of high volume with a mix of both commuter traffic and people getting to their holiday destinations.”

The safest travel day is Thanksgiving, with relatively few people on the road.

The Friday and Saturday after the holiday are safer than the earlier days in the week, but Sunday sees an uptick in traffic as people return home from holiday destinations.

Low visibility can also affect the number of crashes. Higher-than-expected crash numbers tend to occur after 5 p.m. during the Thanksgiving travel period.

“The change in the time zone in Alabama just a few weeks before the holiday will cause more people to be traveling in darkness,” Brown said.

“The combination of late afternoon rush hours with a darkening environment is lethal, and the weekday rush hours should be totally avoided if possible.” Collisions with deer are more than twice as likely during this week, according to the study. Deer are active around dusk or shortly after, a busy drive time for holiday travelers.

Researchers found 84 deer strike crashes during Thanksgiving week during 2015, but they say there have been several hundred that weren’t reported. Crashes where the driver avoids the deer but hits something else are not reported as deer strikes.

Alcohol use was another cause of the increase in Thanksgiving crashes. Citations for driving under the influence were 17 percent more likely during Thanksgiving week than the rest of the year, according to the researchers, and crashes where police officers listed alcohol was a contributing factor were about 25 percent more likely that week.

“The reason for increased alcohol and drug use is the freedom from going to work the following day; thus, each day becomes, for many, like a Saturday, in which typically there is increased alcohol/drug use both late night and the very early morning hours,” Brown said.

Seat belt use was reported as 25 percent lower during Thanksgiving week compared with the rest of the year.

“Don’t think just because it’s a short trip, ‘I don’t really need to buckle this time’ because most crashes happen within 25 miles of your home,” said Rhonda Stricklin, associate director of the Center for Advanced Public Safety.

Crash records for the study were provided by the Alabama Law Enforcement Agency.

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