As soon as possible. Some surveillance systems overwrite footage within days, so waiting can make key evidence harder or impossible to recover.

A partial plate can still help, especially when combined with vehicle color, make, model, direction of travel, location, time, cameras, and witness statements.

A police report is often important after a hit-and-run because it documents that the other driver left and may be required for insurance or DMV reporting.

Useful evidence can include photos, video footage, witness information, vehicle debris, paint transfer, police reports, medical records, and insurance communications.