The first hour: safety first, evidence second
State driver handbooks put the sequence plainly: stop, call 911 if anyone is hurt, and move the vehicles out of traffic if nobody is. Everything on the legal side of a crash comes after that, and none of it is worth a second injury on a live road. Once everyone is safe, the hour that follows produces most of the evidence the claim will ever have, because skid marks are driven over, cars are towed, and witnesses leave.
The reason the order matters is that fault and injury are both proven from the scene. A police report records the officers’ observations and often a preliminary fault finding; photographs fix the position of the cars, the damage, the road and the weather; witness contacts turn “he said, she said” into a corroborated account. An insurer reading the file weeks later sees only what was captured.
Two things people say at the scene cause the most damage later: an apology that becomes an admission of fault, and “I’m fine” that becomes evidence there was no injury. Adrenaline masks symptoms for hours, and whiplash and concussion symptoms commonly appear a day or two later. Be courteous, exchange facts, and leave conclusions to the record.