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The total number of deaths in road accidents in Europe is decreasing, but among the elderly it is rising. With an aging population, this must be addressed to maintain the overall downward trend in fatalities.
The EU-funded SENIORS project has deployed novel methods to ensure the safe mobility of older car occupants, as well as pedestrians and cyclists involved in collisions with cars.
“A raised road safety standard for older road users will improve their mobility and overall satisfaction level, and support the health care system,” says SENIORS project coordinator Marcus Wisch, of BASt in Germany. “Furthermore, the expected results will also influence positively the safety of younger road users.”
Different ages, different injuries
During the project, the researchers conducted comprehensive analysis of road traffic accident and hospital data analysis, in particular comparing older and younger road users. They used this data to develop computational models and physical test tools; the project is working towards hybrid testing approaches involving both.
By examining how and why injuries occur in car accidents, the project team found that older people have different critical body regions. For instance, they are more likely to suffer injuries to the thorax. Measures that reduce such injuries can therefore decrease the proportion of elderly fatalities in road accidents.
SENIORS updated human body models used in crash simulations with important age-related biomechanical factors, particularly changes in rib-cage geometry with age. The project also developed new chest injury risk curves for the most up-to-date frontal crash test dummy.
The development of a generic sled test setup enabled the researchers to conduct comparative physical experiments and simulations for state-of-the-art and future restraint systems, including an airbag, using a prototype “elderly, overweight dummy”.
Biomechanics for car occupants
Active vehicle safety systems, such as emergency braking systems, have great potential for preventing road accidents, but their market penetration requires time and their real-world benefit still needs to be proved through accident data. A complementary approach is to implement passive safety systems incorporating specific protection for the elderly.
Wisch explains that the project focuses on innovative passive vehicle safety systems that can be implemented promptly, to help reach internationally set goals for road-injury statistics in the short to medium term.
“The consequence would be that car manufacturers and automobile suppliers would have to design appropriate solutions for the elderly, such as restraint systems and vehicle fronts,” says Wisch. “In the longer term, the project aims to supply solutions to raise again the safety level of older road users, by using new test tools or adding specific injury criteria for the elderly.”
This area of research is known as biomechanics: where biology and mechanical engineering combine. Describing the effects of road accidents on the skeletal and musculature system of different age groups helps in the design of the most effective passive safety measures.
Regarding the safety of pedestrians and cyclists in collisions with car fronts, SENIORS has developed a new test and assessment procedure. This includes a test tool (named FlexPLI-UBM) that takes into account torso mass and femur injuries. It also includes a Thorax Injury Prediction Tool, which directly addresses thoracic injuries in pedestrian and cyclist collisions for the first time.
“All tests and simulations support the development of updated injury risk functions dedicated for older road users,” says Wisch.