We discovered that Avon and Somerset Constabulary collected separate contributory factor information for years up to 2001. We wrote to the Chief Constable (click here) and have obtained contributory factor data from them for 2001.

Several important questions remain about the data, and we will contact Avon and Somerset as soon as possible for clarification. 

In the meantime, we present preliminary findings. Once the remaining questions have been answered, we will publish full details including source data.

We discovered that 10% of contributory factors were related to excessive speed.
 
 

Just 30% of excessive speed accidents took place in excess of the speed limit, and 2% of excessive speed accidents involved a stolen vehicle.

The 68% of remaining excessive speed accidents involved speeds inappropriate for the conditions. Speed cameras do not measure this sort of speed.
 
 

Avon and Somerset asked for a data preparation fee. Since we're happy to see Police resources expended on Police work, we find this reasonable. In this case the fee was paid by the Association of British Drivers (ABD). Thanks ABD.

Our thanks also to those at Avon and Somerset who have assisted.

Full conclusions to follow when missing details have been incorporated in the data analysis.