But sometimes they're very planned -- a scammer's attempt to rip you off.
Experts say they're seeing more staged accidents and fake injury claims.
"We do see those, if one of our insured is rear ended then the obvious is neck and back injuries," says Gina Conaway, Agent with State Farm Insurance.
Conaway says if there is an injury, they send trained adjustor's to look at medical records to prevent this from happening.
Staged accidents are a bit different, if you rear-end the vehicle in front of you, you're typically held liable for the accident.
Scammers will often slam on brakes or make a complete stop to cause an accident.
"If you rear-end someone, you're at fault and that's where the scam comes in because the scam artist know this," added Conaway.
Which is why experts stress the importance of keeping a safe distance from the car in front of you.
You should also make sure your insurance policy has enough liability to cover you if this happens.
Dale Eaton, owner of Collision Repair Specialists says he sees this type of accident happen often and the biggest mistake people do is not having the right paperwork.
"Somebody can buy insurance and let it lapse and then they actually don't have insurance even though they show you a card," said Eaton.
Even if they do show proof of insurance, it's important to always verify the information yourself and keep your own copy of police records and photos.
Even if it's just a small fender bender, you should always file a police report.
"No matter what, call the police because then there's a report filed," added Eaton.
Experts say make sure you're properly insured.
Even if the accident happens after hours, call your insurance agent to alert them of an accident.
When choosing an auto body shop, make sure the shop is certified and has the proper training.