Gila Albert

Impact of Active Speed Limiters on Traffic Flow and Safety: Simulation-Based Evaluation

Speed limiters, which control the maximum speeds of vehicles so equipped, have been proposed in recent years as speed management tools. A simulation-based evaluation is described of the impact of a wide installation of speed limiters on traffic flow characteristics and on safety. Microscopic traffic simulation is used; it models the driving behavior of individual vehicles in detail and so captures not only the impact of speed limiters on equipped vehicles but also the interaction between equipped and unequipped vehicles and the resulting impact on the latter. In the experiment, the impact is evaluated of preset speed limiters for two limiter-set speeds, 100 km/h and 120 km/h, at various desired speed distributions and congestion levels. The simulation results show that speed limiters can reduce average traffic speeds up to 10% and that the variability of traffic speeds may also be lowered. Consequently, a significant reduction in accident rates might be achieved.

The challenge of safe driving among elderly drivers

The challenge of ageing has two key aspects with regard to driving: mobility and safety. It is necessary for elderly adults to preserve independent mobility and activity; however, physical frailty and cognitive limitations have negative effects on their safety. Therefore, the issue of driving, and more specifically, the fostering of safe driving of old people, is crucial, especially due the increasing number of elderly people holding a driving license. The purpose of this Letter is to point out the complexity of elderly driving and to suggest countermeasures by acknowledging that obtaining the correct balance between safety and mobility of older drivers is a complicated and sensitive task. To address this issue, the authors suggest accommodating their driving behaviour and patterns, in light of the deteriorating driving skills, by integrating social and policy procedures and use of emerging technologies. Policy steps to support elderly drivers and their loved ones by gradually controlling driving of elderly population when this becomes risky to them may serve as a desired countermeasure according to a proved tool such as technology. Utilisation of advanced technologies can help to monitor travel and driver behaviour and ability to make the necessary alterations, based on elderly driving skills.