Abstract Road geometric design standards provide various possibilities for merging freeways with a decreasing number of lanes. In this study, an alternative design (i.e. taper design) is investigated and compared with the standard design under three different heavy vehicle compositions to understand driving performance in relation to the flow of traffic. Taper design is not always the first choice in the road geometric design guidelines and the designer has to provide arguments for selecting this design. Taper design and its comparison with other alternatives are also not well explored in literature. In this study, a driving simulator was used to examine and compare the performance of these two designs under different heavy vehicle compositions. Qualitative results showed that the perceived safety was better for the standard design compared to the taper design. Mean speed, acceleration, standard deviation of acceleration/deceleration, and cumulative lane changes were chosen as behavioural parameters to compare these two designs using MANOVA and repeated measures ANOVA. Results revealed that drivers’ discomfort in performing merging manoeuvres was greatest in case of a taper design and when the percentage of heavy vehicles was moderate (15%). Overall, the standard design was found to be more favourable. Practitioner summary: Driving behaviour at merging freeways with a decreasing number of lanes is underexplored. We analysed safety in driving behaviour considering heavy vehicles for taper and standard designs provided in Dutch guidelines using a driving simulator. The standard design was found to be safer and the presence of moderate heavy vehicles caused more disturbances in driving behaviour.

中文翻译：

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与锥形设计相比，标准高速公路合并设计支持更安全的驾驶员行为：驾驶模拟器研究

摘要 道路几何设计标准为合并高速公路和减少车道数量提供了各种可能性。在这项研究中，研究了替代设计（即锥形设计），并在三种不同的重型车辆组合下与标准设计进行了比较，以了解与交通流量相关的驾驶性能。锥形设计并不总是道路几何设计指南中的首选，设计师必须提供选择这种设计的论据。文献中也没有很好地探讨锥度设计及其与其他替代方案的比较。在这项研究中，驾驶模拟器用于检查和比较这两种设计在不同重型车辆组合下的性能。定性结果表明，与锥形设计相比，标准设计的感知安全性更好。平均速度、加速度、加速度/减速度的标准偏差和累积车道变化被选为行为参数，以使用 MANOVA 和重复测量 ANOVA 比较这两种设计。结果显示，在锥形设计和重型车辆比例适中 (15%) 的情况下，驾驶员在执行合并操作时的不适感最大。总体而言，发现标准设计更有利。实践者总结：在车道数量减少的情况下合并高速公路时的驾驶行为尚未得到充分探索。我们使用驾驶模拟器分析了考虑重型车辆的荷兰指南中提供的锥形和标准设计的驾驶行为安全性。