I’ve found STATS 20, Instructions for the Completion of Road Accident Reports which details which codes and when they should be used for completing STATS 19.
Annex 4 of this document lists the codes for Contributory Factors with an explanation of what they mean. I counted 76 different contributory factors (77 if you include ‘Other - please specify’)
Code 306 is used for exceeding speed limit, and the guidance note that accompanies it states:
Driver/rider caused, or contributed to the accident, by exceeding the posted speed limit. This code should also be used in cases where the actions of another road user were the immediate cause of the accident but a speeding vehicle also contributed to causing the collision.
Includes exceeding variable speed limits (eg. on motorways) and speed limits based on vehicle type (including towing).
Use this code (not code 307) if the driver/rider was exceeding the speed limit and travelling too fast for the conditions Code 307 is used for ‘travelling too fast for conditions’ and the guidance note states:
Driver/rider was travelling within the speed limit, but their speed was not appropriate for the road conditions and/or vehicle type (including towing), and contributed to the accident.Statistics can be quite revealing, but how they are recorded needs to be understood before any conclusions can be drawn.
In the report submitted by the police officer, if a driver involved in an accident is both exceeding the speed limit and travelling too fast for the conditions, the contributory factor recorded is only the one for exceeding the speed limit, code 306.
Does anyone know how it is decided if a vehicle in an accident was exceeding the speed limit? I would have thought that for code 306 to be selected, there would have to be some compelling, independent and accurate evidence of the vehicle’s speed to prove that it was exceeding the limit, whereas travelling too fast for conditions is more of a subjective assessment and easier to prove by the mere fact that there has been an accident especially in adverse driving conditions. This might be one reason why there appears to be a bias towards code 307.
The IAM seem, however, to be stating the blindingly obvious, but using the stats in a poor way to try to prove their point, if indeed anyone was in any doubt that travelling too fast for the conditions was perfectly possible without exceeding the speed limit.