Conclusions and recommendations
Cyclists are no pedestrians; most studies about the safety for vulnerable users mention
countermeasures to increase the safety for pedestrian and bicyclists. However most of
these studies are based on pedestrian’s safety only. This study shows that not all safety measures for pedestrians are efficient for bicyclists. Attention for the specific
kinematics of bicyclists in future regulations and during the development of safety
systems is needed.
From literature it was found, that bicycle safety is an issue that is more serious in the
Netherlands than in other countries of the European Union. The Netherlands are the
only country were each year the number of fatal cyclists accidents exceeds the number of fatal pedestrian accidents.
From both literature and parameter study it was found that most dominant injuries
occurring in bicycle to car accidents were head injuries. Also, they were most often
causative for cases with fatalities. Lower leg injuries tended to be the most severe
injuries, however they were not life threatening. Elderly people run a higher risk of
obtaining serious injuries than younger people.
From the parameter study it was found, that the general car geometry parameters as
bonnet length or bonnet – windscreen angle have no influence on obtained injuries. It
was only found, that lower cars and lower bonnet leading edge heights tend to result in
lower pelvis and head 3ms acceleration. No car height or bonnet leading edge reference
height can be recommended though, as the reduction with respect to obtainable injury
was found to be highly depending on car speed, bicycle orientation, cyclist – bicycle
combination and the combination of these parameters.
The speed of the car at time of impact is the core parameter with respect to obtained
injuries, impact velocities, and impact location. Therefore, the most effective way to
reduce cyclist injuries in car to bicycle accidents is to make sure cars do not drive faster than allowed and necessary.
Integrated safety systems such as brake assists and autonomous braking are not only
effective for pedestrian safety but also for cyclist safety.
Current regulations for pedestrian safety are less effective for cyclists. Though small
cyclists as the small female of the parameter study and young children are still covered
to some extend for car speeds _x0002_ 30 km/h, average adults and car speeds > 30 km/h are not covered anymore. Therefore it is proposed to extend the current head impact
protocol towards the windscreen.
Exterior airbags as under development by Autoliv were shown to be very effective for
cyclists as well, showing a potentional HIC reduction of about 75%. Special attention
though will have to be paid to the impact location of a cyclists’ head as it hits much
higher than a pedestrian head.