US and UK Field Rollover Characteristics 2001-01-0167

In this study, US and UK accident data were analyzed to identify parameters that may influence rollover propensity to analyze driver injury rate. The US data was obtained from the weighted National Automotive Sampling System (NASS-CDS), calendar years 1992 to 1996. The UK pre-roll data was obtained from the national STATS 19 database for 1996, while the injury information was collected from the Co-operative Crash Injury Study (CCIS) database.

In the US and UK databases, rollovers accounted for about 10% of all crashes with known crash directions. In the US and UK databases, most rollovers occurred when the vehicle was either going straight ahead or turning. The propensity for a rollover was more than 3 times higher when going around a bend than a non-rollover. In the UK, 74% of rollovers occurred on clear days with no high winds and 14% on rainy days with no high winds. In the US, 83% of rollovers took place in non-adverse weather conditions and 10% with rain. In the US and the UK, more than 50% of rollovers happened during daylight. However, compared with non-rollover incidents, US and UK rollovers had a higher propensity to occur with sleet/fog or snow and in the dark without streetlights. In the UK, 76% of rollovers took place on roads with a speed limit of 50 mph (80 kph) and above, while in the US, the rate was 51%. In the US, drivers were most often distracted by people inside and outside their vehicle or when eating and/or drinking, and falling asleep.

The results indicate that pre-rollover characteristics are somewhat similar in the US and in the UK. Rollovers were more likely to occur with sleet/fog or snow and in the dark than non-rollover crashes. Vehicles that were traveling straight on a highway or going around a curve were most likely to roll.

In this study, the overall injury distribution was similar in US and UK drivers. For belted and unbelted drivers, serious injuries were most frequent in the head and in the thorax, emphasizing the need to provide protection in both these areas. The pre-rollover and injury information obtained in this study may thus be useful for the development of global preventive measures.