A new ’On-The-Spot’ (OTS) accident research project is now underway in the UK. This project enables expert investigators to attend the scene of an accident within 15 minutes of the incident occurring, which allows the collection of accident data that would otherwise be quickly lost. This paper considers previous studies and the justification for a new research approach before describing methodology used on the spot and during subsequent follow-up research. Investigations focus on all types of vehicles (including damage, failures, features fitted and their contribution); the highway (including design, features, maintenance and condition); the human factors (including drivers, riders, passengers and pedestrians); and the injuries sustained. Five hundred crashes will be studied in depth each year. The project objectives include establishing an in-depth database that will permit analyses to better understand the causes of crashes and injuries, and assist in the development of solutions.