The Department for Transport provides national data on road casualties and explains how the data on personal injury collisions is collected and recorded by the police.
Summary information on maps of collisions resulting in personal injury recorded by the police on any road in Great Britain can be viewed on CrashMap.
More detailed information and bespoke data requests for locations within Surrey can be obtained (for a fee to commercial organisations) by emailing the joint Surrey Sussex collision data unit at RoadSafetyData@sussex.police.uk