Characteristics of low speed accidents with buses in public transport.

Low-speed accidents with buses in public transport in the city of Uppsala during the years 1986-2000 are coded in 17 variables concerning mainly physical properties of the accident. The taxonomy uses classifications from existing schemes, but some are altered and some new are added to capture common features of reports of bus accidents in this population. It is found that side contacts and singles are the most common accidents, and that more than a quarter of all accident involvements occurs at bus stops. Inter-rater reliability calculations for the categories show that all except one have reliabilities above 80%. The level of internal validity, calculated as agreement of frequencies between time periods, is acceptable, despite many possible sources of change and bias. It is argued that the validity of this database far exceeds that of the, for research purposes normally used, non-company self-reports, state- and police-archives, due to more extensive reporting and corroborating evidence. The practical usefulness of these results and accident taxonomies in general is discussed.