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Published in Sara J. Czaja, Walter R. Boot, Neil Charness, Wendy A. Rogers, Designing for Older Adults, 2019
Sara J. Czaja, Walter R. Boot, Neil Charness, Wendy A. Rogers
Several strategies are recommended to reduce the left turn crash risk of older drivers. Perhaps the safest solution is to eliminate the need to judge gaps in traffic altogether by implementing a protected left turn phase in which left turning cars receive a green arrow and oncoming vehicles are stopped by a red signal. Otherwise, the left turning vehicle sees a red arrow indicating that they cannot turn. While safe, this phasing can negatively impact traffic flow by preventing left turning vehicles from taking advantage of safe gaps in traffic when available. Left turns may be especially challenging when the opposing left turn lane is occupied by vehicles, limiting the view of oncoming traffic. Here, an effective solution is to shift the opposing left turn lanes to the right to allow older drivers a less obstructed view of oncoming traffic and more time to estimate gaps (Figure 9.3). Replacing a signalized intersection with a roundabout can also benefit older drivers. Traffic flowing through roundabouts is typically slower compared to signalized intersections, making judging a safe gap in traffic easier. Further, roundabouts eliminate the possibility of severe right-angle crashes. However, education is key for older drivers for whom the use of roundabouts may be novel, especially when drivers first encounter a multi-lane roundabout. These educational materials (e.g., brochures and tip cards) should follow the principles of designing instructional materials for older adults (Charness et al., 2017).
Design vehicles and roundabout safety—review of Croatian design guidelines
Published in Gianluca Dell’Acqua, Fred Wegman, Transport Infrastructure and Systems, 2017
Š. Bezina, I. Stančerić, S. Ahac
Compared to the conventional intersections, roundabouts can provide numerous benefits, such as improved intersection safety and capacity, reduced maintenance costs and air pollution (Ahac et al. 2014; Hydén et al. 2000; Mandavilli et al. 2003). Their design process is highly iterative and usually consists of several steps: – initial geometric design of elements,– performance and safety checks (swept path analysis, fastest path analysis and sight distance tests), and– final design of elements.
Human-Like Decision Making for Autonomous Vehicles with Noncooperative Game Theoretic Method
Published in Peng Hang, Chen Lv, Xinbo Chen, Human-Like Decision Making and Control for Autonomous Driving, 2023
Peng Hang, Chen Lv, Xinbo Chen
To further study the human-like decision making of AVs in complex driving environment, the urban scenarios are usually investigated, e.g., unsignalized roundabouts. Unsignalized roundabout intersections are usually considered to be more complex and challenging than crossroad intersections, with respect to multi-vehicle interactions [174, 263, 43]. A roundabout is defined as a circular intersection in which all vehicles travel around a circular island at the center with the counter-clockwise direction (driving on the right) [3]. Compared to crossroad intersections, traffic lights are not necessary for roundabouts to control the traffic flow. Therefore, for the entering vehicles, a complete stop may not be required. As a result, the traffic delay can be decreased, and the traffic capacity can be improved [187]. In general, the traffic rules at roundabouts are defined as follows: (1) Circulating vehicles have the priority over entering and merging vehicles; (2) exiting vehicles have the priority over entering vehicles; and (3) large vehicles have the priority over small vehicles. The aforementioned rules are able to bring remarkable advances to the traffic efficiency and safety at roundabouts [176]. Although the above traffic rules can help reduce the traffic conflicts, with the increase of traffic flow, especially during peak hours, congestion and conflicts are inevitable due to different travel objectives, and personalized driving characteristics and driving behaviors of human drivers. Therefore, the complex unsignalized roundabout urban scenario is a great challenge for AVs. Human-like decision making is effective in dealing with the interaction and decision making of AVs in complex conditions.
Safety analysis of roundabouts and avoidance of conflicts for intersection-advanced driver assistance systems
Published in Cogent Engineering, 2022
Roundabout, which is spreading all over the world due to the advantages of low maintenance cost, smooth traffic flow, and safe operation, is a kind of flat intersection that rotates around the round traffic island in the center of the intersection without traffic lights and passes through the intersection. The basic principle is to yield to a car driving on a roundabout inside the intersection. However, as the number of roundabouts increases, various roundabouts are constructed according to the conditions of surrounding roads, and special types of accidents caused by inexperienced drivers at roundabouts are also increasing. For beginner driving, that is, early autonomous driving and Advanced Driver Assistance System (ADAS), more difficulties can be exacerbated than in the case of a four-way intersection. In addition, as the diameter of the central transportation island is reduced and traffic volume increases due to space constraints, collision accidents are increasing, which leads to a reduction in speed, which impedes smooth traffic flow.
Unpacking older drivers’ mobility at roundabouts: Their visual-motor coordination through driver–vehicle–environment interactions
Published in International Journal of Sustainable Transportation, 2019
Qian (Chayn) Sun, Jianhong (Cecilia) Xia, Jonathan Foster, Torbjörn Falkmer, Hoe Lee
The use of modern roundabouts is meant to improve the safety at intersections by minimizing conflicts and reducing drivers’ speed. However, roundabout performances can be degraded if precautions were not taken during either the design or the operational stage (Montella, 2011). Geometric design deficiencies were identified as contributory factors in roundabout crashes (Montella, 2011). Knowledge and findings on the safety of the roundabouts are helpful for planners and designers in refining the design criteria. For road users, the information sampling requirement increases with the increasing road curvature, more frequent information and corrective steering input are therefore needed, which lead to an increased eye-steering correlation and more efficient coordination (Land & Horwood, 1995; Miall & Reckess, 2002; Tsimhoni & Green, 2001). Understanding older drivers’ visual-motor coordination while they negotiating roundabouts becomes particularly important for older drivers’ mobility and safety.
A safety analysis of roundabouts and turbo roundabouts based on Petri nets
Published in Traffic Injury Prevention, 2019
Jesús Balado, Lucía Díaz-Vilariño, Pedro Arias, Ana Novo
External transitions model the relationship of the lanes of the roundabout with the lanes of the roads entering and leaving them. Entrance to the roundabout is made in the lane that best suits the desired exit or on the outer circulatory lane, depending on the law in force in each country. The change from position to can only be made if there is no car in and no cars arrive through the lanes of the roundabout that could interfere with the incorporation The traffic rules establish that the exit of the roundabout must be made from the outer lane The only condition to leave the roundabout is the nonexistence of vehicles in the exit position External transitions are represented with PNs in Figure 4.