An investigation into the relationship between rainfall and road accident frequencies in two cities.

A statistical analysis has been made of the effect of moderate and heavy rainfall on accident frequencies recorded for London and Huddersfield for a period of 1 year. The analysis attempts to measure and compare these effects separately in (1) four specific periods of the day (night, rush hours, mid-day and rest-of-day); (2) four seasons of the year and (3) the complete period under study (whole-year analysis).