The Effects of Cyclists Present at Rural Intersections on Speed Behavior and Workload of Car Drivers: A Driving Simulator Study

<b>Objective:</b> The objective was to gain insight into how the number of cyclists, the cyclist's approach direction, and the cyclist's action affect the speed and mental workload of drivers approaching rural intersections. In addition, the effects of a speed-reducing measure on the interaction between cyclists and motorized traffic were examined. <b>Methods:</b> An experiment was conducted in a moving-base driving simulator. Thirty participants completed 3 runs each in 3 conditions: a baseline, a plateau, and a chicane condition. Participants drove an 80 km/h rural distributor road with 8 intersections. Eight cyclist scenarios were developed varying in the number of cyclists and the direction from which they approached the participants’ lane. The Peripheral Detection Task was used to measure workload objectively and continuously. <b>Results:</b> A plateau ahead of the intersection resulted in drivers entering the bicycle crossing with lower driving speeds but did not result in less serious potential conflicts compared to intersections without the speed-reducing measure. With respect to the presence of cyclists, drivers approaching the intersection without cyclists reached a minimum speed at a greater distance from the bicycle crossing compared to approaching the intersection with multiple cyclists in the baseline condition. At intersections with plateaus, drivers drove slower when encountering multiple cyclists compared to no cyclists. At intersections without the speed-reducing measure, drivers drove slower, decelerated stronger, and decelerated at a shorter distance to the bicycle crossing when encountering a suddenly crossing cyclist compared to a yielding cyclist. <b>Conclusions:</b> Although drivers have the right of way at rural intersections, drivers’ speed behavior was affected by the number and action of cyclists. From a road safety point of view, driving speeds at rural intersections need to be further reduced to limit the seriousness of potential conflicts between cyclists and motorized traffic.

**研究目标：** 本研究旨在揭示骑行者数量、骑行者趋近方向及骑行行为对乡村交叉口附近驾驶员行驶速度与心理负荷的影响规律；此外还探究了减速措施对骑行者与机动车交通之间交互行为的作用效果。**研究方法：** 本研究依托移动基座驾驶模拟器（moving-base driving simulator）开展实验。30名受试者在基线、减速台（plateau）及减速弯道（chicane）三种实验条件下各完成3次驾驶流程。受试者需在一条限速80 km/h的乡村集散道路上行驶，该道路共设置8处交叉口。研究设计了8种骑行者场景，通过调整骑行者数量及其驶向受试者所在车道的趋近方向实现变量控制。本研究采用外周检测任务（Peripheral Detection Task）实现对驾驶负荷的客观、连续监测。**研究结果：** 相较于未设置减速措施的交叉口，在交叉口前设置减速台可使驾驶员以更低车速驶入自行车过街区域，但并未降低潜在冲突的严重程度。针对骑行者数量的影响分析显示：在基线条件下，当交叉口无骑行者时，驾驶员会在距离自行车过街区域更远的位置达到最低行驶速度，这一表现不同于有多名骑行者的场景；而在设置减速台的交叉口处，驾驶员遭遇多名骑行者时的行驶速度会显著低于无骑行者的场景。在未设置减速措施的交叉口，当遇到突然横穿的骑行者时，相较于主动避让的骑行者场景，驾驶员会以更低车速行驶、制动强度更大，且会在距离自行车过街区域更近的位置开始减速。**研究结论：** 尽管乡村交叉口处机动车享有优先通行权，但驾驶员的行驶速度行为仍会受到骑行者数量及骑行行为的影响。从道路交通安全视角出发，需进一步降低乡村交叉口处的行驶车速，以限制骑行者与机动车交通之间潜在冲突的严重程度。