Motorists heading to Grandma’s or making that last-minute trip to the grocery store on Wednesday should beware that the chances of being involved in a rear-end collision or a parking lot mishap are 24 percent higher on the day before Thanksgiving, a new survey of claims data has found.

Insurer Progressive looked at data from 2012 and also found that crashes involving two or more vehicles increased by 17 percent on “Black Wednesday.” Drivers also were 14 percent more likely to hit a mailbox, concrete median or other fixed object between 3 a.m. on the day before Thanksgiving and 3 a.m. the next day.

“Black Wednesday isn’t a day that pops up on most people’s radar, but the mixture of relatives in town, students home from school and no work the following day makes for a busy day on the roads,” said Tricia Griffith, claims group president for the nation’s fourth-largest auto insurer.

Overall, Minnesota saw a 24 percent increase in the frequency of automobile crashes, fender-benders in parking lots, rear-end wrecks, motorists hitting cars parked on the street and vehicles hitting private or public property, a Progressive spokeswoman said.

In other places, the risk was much higher.

Maryland took the honors as the most dangerous place to be on Black Wednesday, with crash frequency up 61 percent. That was followed by Oregon at 60 percent, Illinois and Iowa at 38 percent, and North Carolina at 35 percent, the insurer said.

A company spokeswoman gave these tips for those heading out on Wednesday:

• Pay extra attention in parking lots, especially when backing out of spots. Use passengers as an extra set of eyes.

• Maintain more distance between you and the vehicle in front of you. That will give you more time to slow down to avoid a rear-end crash — and decreases the chances of being hit from behind.

• Have a designated driver if you are heading out and folks will be drinking. Or use services such as Sober Car.