1. You can move the cars out of the road so no one else is hurt. You don't have to "preserve the scene" until the cops get there.
2. If anyone was hurt, or there was more than $500 of damage done to the cars, the police will make a "Crash Report." Usually a Highway Patrol Trooper shows up. Cooperate with the police with a statement. Don’t worry, statements made to the police are generally not admissible for the civil case. But don’t let the other guy listen to what you say. The cop should not let him, but they are just cops, not lawyers.
3. Get medical care if you were hurt. You only have 14 days to get care or you can not get the free money that pays for your care. It is a new law.
4. If you are hurt, and it was not your fault, call an attorney. We prefer you call us, but ANY attorney is better than no attorney. All attorneys are required to learn about personal injury in law school before they are allowed to graduate, After talking to an attorney THEN you can start calling insurance companies. You don't have to call your insurance company, or any insurance company, right away, They can use your statement against you. An attorney can only help you. Even if you call an attorney who usually works for the insurance company of the person who hit you, that is ok. That attorney, or their staff, will thank you for your call and tell you to call someone else. They can not use your call against you, because calling a lawyer is confidential.
5. Save every piece of paper that you got. From the other driver. From the cop. From the emergency room. From the doctor. Your lawyer loves all evidence, no matter how trivial, or crumpled up