It has been a controversial issue for the effect of ageing population on driving safety. Apparently, drivers’ physiological and cognitive performances deteriorate with age. However, older drivers may compensate for the elevated risk by adjusting their behaviors, known as compensatory strategy. Despite the extensive research on this topic, the compensatory strategy of older professional drivers is not well understood since many studies focused on the differences in compensatory behavior between older and young drivers. Professional drivers tend to be more skillful and able to cope with the unfavorable driving environments, thus presenting a higher capability to mitigate the risk. This study attempts to examine the compensatory behavior and its safety effect amongst older professional drivers, as compared to those of older non-professional drivers, using the driving simulator approach. In the driving simulator experiment, participants were asked to follow a leading vehicle for one hour, and two sudden brake events were presented. 41 (mid-aged and older) drivers completed the driving tests. Each participant was required to complete a car-following test, either under high or low traffic flow conditions. Performance indicators include driving capability (i.e. lateral control, longitudinal control, and brake reaction time) and compensatory behavior (i.e. average speed, and time headway). Additionally, two modified traffic conflict measures: time exposed time-to-collision (TET) and time integrated time-to-collision (TIT) are applied to indicate the traffic conflict risk. The random parameter Tobit models were estimated to measure the association between conflict risk and driver attributes, and random intercept models were used to assess other driving performance indicators. Results show that despite the impaired lateral control performance and longer brake reaction time of older drivers, the likelihood of severe traffic conflict of older drivers is lower than that of mid-aged drivers. Furthermore, though both older professional and older non-professional drivers adopted longer time headway, the reduction in the risk of severe traffic conflict is more profound among the older professional drivers. Such findings suggest that older professional drivers are more capable of mitigating the possible collision risk by adopting the compensatory strategy, as compared to older non-professional drivers. This justifies the existence of compound effect by the compensatory strategy of older driver and better driving skills of professional driver. This research provides useful insights into driver training and management strategies for employers, as older drivers would become a major cohort in the transportation industry.

人口老龄化对驾驶安全的影响一直是一个有争议的问题。显然，驾驶员的生理和认知表现会随着年龄的增长而恶化。但是，年长的驾驶员可以通过调整其行为来补偿高风险，这被称为补偿策略。尽管对此主题进行了广泛的研究，但由于许多研究集中在老年和年轻驾驶员之间的补偿行为上的差异，因此对老年职业驾驶员的补偿策略还没有很好地理解。专业的驾驶员趋向于更加熟练并且能够应对不利的驾驶环境，因此具有减轻风险的更高能力。这项研究试图检验与专业人士相比，老年职业驾驶员的代偿行为及其安全效果，使用驾驶模拟器方法。在驾驶模拟器实验中，要求参与者跟着领先的车辆行驶一个小时，并提出了两次突然的制动事件。41名（中老年）驾驶员完成了驾驶考试。在高流量或低流量的情况下，每个参与者都需要完成一次跟车测试。性能指标包括驾驶能力（即横向控制，纵向控制和制动反应时间）和补偿行为（即平均速度和时距）。此外，还应用了两种修改的交通冲突度量：暴露时间碰撞时间（TET）和时间综合碰撞时间（TIT）来指示交通冲突风险。估算了随机参数Tobit模型，以测量冲突风险与驾驶员属性之间的关联，随机截距模型用于评估其他驾驶性能指标。结果表明，尽管老年驾驶员的横向控制性能受损，制动反应时间更长，但老年驾驶员发生严重交通冲突的可能性低于中年驾驶员。此外，尽管年长的专业驾驶员和年长的非专业驾驶员都采用了更长的时间，但在年长的专业驾驶员中，严重交通冲突风险的降低更为明显。这些发现表明，与年长的非专业驾驶员相比，年长的职业驾驶员通过采取补偿性策略更有能力减轻可能发生的碰撞风险。这证明了老年驾驶员的补偿策略和专业驾驶员更好的驾驶技能会产生复合效应。