What triggers road traffic fatalities among older adult drivers? An investigation based on the Swedish register for in-depth studies of fatal crashes.

INTRODUCTION

Road traffic fatalities among drivers result not only from erroneous driving manoeuvres. They can also be triggered by poor mental or physical health like suicidal acts and acute disease attacks, the latter being more frequent with age. There are few studies comprising all the different triggers of fatal crashes among older drivers and on how these triggers evolve over time. This Swedish national study aims to investigate this, considering drivers 50+ years.

METHOD

For the period 2010-2019, data on non-commercial car drivers aged 50 and older were extracted from the Swedish Transport Administration's in-depth studies of fatal crashes, compiled in a register encompassing all road traffic fatalities. The crash triggers reported were classified as suicide, acute disease, own manoeuvre (single or other type of crash), external, and undetermined. Total and annual frequencies were presented by crash trigger, overall and stratified by sex and age groups.

RESULTS

In total, 762 fatalities were identified and with 709 of them, it was possible to classify the crash trigger: 12% resulting from suicide; 29% from acute disease; 49% from the driver's own manoeuvre; and 10% from an external crash trigger. Suicides increased from 9% in average 2010-2014 to 15% in 2015-2019 while acute disease decreased (from 32% to 27%). The overall male-to-female ratio was 4.5, and as high as 8.7 for acute disease. The relative importance of each trigger varied with age with, for instance, acute disease being more frequent in the two younger age groups; 31% for 50-64 and 52% for 65-79 years old drivers, while own manoeuvre was more prominent for drivers aged 80 and older (23%).

CONCLUSION

The distribution of the four different triggers of road traffic fatalities varies only slightly over time and, a majority are triggered by the driver's own manoeuvre. However, a substantial proportion, about four out of ten,are triggered by a health condition, of which some are suicide but the major part an acute disease, mainly cardiovascular. In some instances, such crashes can be harmful to other road users. Having in mind the need for safety and mobility of older drivers and the protection of all road users, there is a need for the promotion of road safety policies that encompass a wider range of measures to help reducing the likelihood of fatal and severe crashes to happen e.g., targeting incapacitated drivers.