Injury and collision data from London’s Helicopter Emergency Medical Service (HEMS) and the UK’s Police fatal files were used to quantify and describe the nature of pedestrian head injury and investigate the causes.

The HEMS data relating to all pedestrian accidents since 2000 was analysed with respect to their injuries, and the cost of these injuries was estimated using the time they spent on the ward and/or in intensive care. In addition to the HEMS data, Police fatal files containing details of fatal pedestrian impacts with the front of cars registered in 2000 or newer were analysed. These included post-mortems, which were coded using the Abbreviated Injury Scale. Although the fatal file sample was limited in size, it had the advantage of containing photographs of the accident and many other pertinent details. This enabled the causes of individual injuries to be determined. The head injuries seen in the HEMS data were then compared to the injuries in the fatal files .

The HEMS dataset contained 746 pedestrians struck by motor vehicles, with 2,974 recorded injuries. 34 fatal pedestrian accidents were analysed using the Police fatal files.

The analysis of the HEMS data showed that the most frequent and costly injuries were to the head and legs. Head injuries of fatally injured adults were found to be principally caused by contact with the windscreen and surrounding structure.

This research highlights the potential of hospital data to be an important tool in accident research, as the injury information can provide evidence of the effects of the changing vehicle fleet, and what injuries should be prioritised in the future. The paper also begins to quantify the proportion of the most serious head injuries (suffered by fatalities) which are caused directly by the vehicle, compared with secondary impacts with the ground or other objects.