Immediately take a photo or write down the license plate number. It is imperative to record this vehicle information ASAP. Call 911 if anyone needs medical attention.
Ask bystanders if they caught the incident. Ask if anyone who witnessed the accident would be willing to provide their contact information in the event that insurance needs to corroborate the events. Exchange phone numbers and request insurance information with the driver. This will be valuable in seeking insurance claims for medical expenses should you require them.
Call both 911 and your local customer service staff.
Record as much of the damage as you possible and ask witnesses to stay at the scene to offer statements.