People who are most at risk in traffic are known as “vulnerable road users.” Since pedestrians and two-wheelers are more in danger of harm in collisions with vehicles than other road users, they are particularly in need of protection from such collisions. Therefore, vulnerable road users are primarily those who are not covered by an outer shield. The road users who are least likely to harm other users of the road are pedestrians and cyclists, but motorized two-wheelers, with their heavier equipment and faster speeds, may be a threat to others. The focus of the scientific expert group’s mandate is consequently on pedal bikers and pedestrians.

In actuality, it should be mentioned that while in certain nations mopeds (or light motorcycles) are recognized as motorcyclists in the eyes of the law and in other countries, mopeds are treated as bicycles. Both methodologies provide different evaluation results about the effects of various infrastructure changes targeted at enhancing bicycle or two-wheeler safety, making it rather difficult to compare accident and risk data between nations. Therefore, it will be necessary to consider the actual situation of two-wheelers in each country when interpreting both the review of current experience in protective measures for vulnerable road users and the recommendations for prospective safety policies.

Some road users are more at risk than others, including the young, the elderly, and people with disabilities. Elderly adults exhibit a steady decline in their capacity to handle challenging traffic circumstances, which increases their risk of being involved in an accident. The lesions acquired in a collision may have more severe effects on them than on people in the younger age groups since they are also growing physically frailer. Because of this, most senior persons who are conscious of their limitations tend to avoid traffic, which limits their mobility and the range of their social interactions. As a result of this trade-off between mobility and safety, accident rates are typically lower than would be expected given the reduced exposure to traffic, which may persuade decision-makers to overlook the unique issue of older pedestrians and cyclists.

Any person who has a physical, sensory, or mental impairment that limits their movement is said to be disabled. Typically, they are pedestrians who are either walking or using a wheelchair; some may also be cycling. The disabled, like the elderly, are more likely to be involved in an accident in congested areas of the road or on elements of the infrastructure that are inaccessible to them. In some cases, they may also have a lesser capacity for injury recovery. Children are especially susceptible to road users because their capacity to deal with traffic declines as they get older and stays quite low for the first nine or ten years of life. Therefore, they are extremely vulnerable in any situation with large or swift motorized traffic, poor visibility, or when drivers tend to pay more attention to other cars and ignore pedestrians or cyclists.

Vulnerable road users are not one single group but rather a collection of individuals with a variety of traits, lifestyles, and behavioural tendencies who share the challenge of adjusting to motorized traffic in a setting that has rarely been created with them in mind.