Road Block: You’re involved in a fender bender. What’s the first thing you should do?

Best Route: If someone has been injured, call the police, as it’s a crime to leave any accident that results in personal injury. Should you need a tow, contact AAA if you’re a member; otherwise call your insurer or the state patrol. If no one is injured, the damage is minimal, and you’re not blocking traffic, you may not need to call the police — and in many municipalities, they may not respond to minor incidents anyway. Instead, collect as much information as you can: all drivers’ and witnesses’ names, addresses, phone numbers, insurance details, and driver’s-license and license-plate numbers. It’s also a good idea to take photos of the damage and any identifying features of the location.

Later, call the nonemergency number for the police department in the area where the accident happened and ask how to file an accident report. (In most states, depending on the amount of damage, you’re required by law to file a report, so opting not to would be considered illegal.) You’ll usually need to pick up a form, or download it from the Internet, and there will be a strict time frame for filing the paperwork, typically within 72 hours of the incident.

Road Block: After an accident, the other person admits that it’s his fault. But to protect his premium, he wants to pay you directly rather than filing an insurance claim.

Best Route: There’s no problem legally or financially with letting him do it that way, as long as the damage is minimal and you’re absolutely sure nobody is hurt, says consumer advocate Remar Sutton. But, even then, going off the books is risky.

“About 10 or 15 percent of the time, it turns into a nightmare,” says Sutton. The other driver may balk when he sees your repair shop’s estimate and ask you to let his place do the work, but who knows how good that shop is, how convenient it is to get to, or how fast it will complete the repair? You may also have a hard time collecting for the rental car you’ll need while your car is in the shop, or for an accident-related problem, like a misalignment, that shows up only later.

The bottom line is you need to decide right at the scene whether the other person seems trustworthy, says Carolyn Gorman, vice president of the Insurance Information Institute, a trade group. “If you’re going to take the gamble, you need to say, ‘We’re going to play by my rules. We’re going to use my body shop. I’ll need a rental car. I’ll need all your insurance information, and I’ll be filing a police report and informing my insurance company about this incident.’”