Design and operation of dedicated lanes for connected and automated vehicles on motorways: A conceptual framework and research agenda

Dedicated Lanes (DLs) have been proposed as a potential scenario for the deployment of Automated and/or Connected Vehicles (C/AVs) on the road network. However, evidence-based knowledge regarding the impacts of different design configurations, utilization policies, and the design of their access/egress on traffic safety and efficiency is limited. In order to develop an adequate design for DLs, first, a conceptual framework describing the relations and interrelations between these factors and traffic safety and efficiency is needed. Therefore, the main aim of this paper is to develop a conceptual framework accounting for the factors that could affect the safety and efficiency of DLs. This conceptual framework is underpinned based on relevant literature on how the deployment of C/AVs, driver behaviour, and DL design and operation affect traffic safety and efficiency. Based on the conceptual framework, the knowledge gaps on DL design for C/AVs were identified and a research agenda, including prioritization of the research needs, is proposed. Following the developed conceptual framework, the necessary building blocks for investigating the impacts of different design configurations, utilization policies, and the design of their access/egress on traffic safety and efficiency are: (1) to specify the types of vehicles with certain capabilities allowed to drive on DLs; (2) to incorporate existing algorithms of C/AVs, which reflect more realistically their behaviour, in both driving simulator experiments and microscopic simulation; (3) to translate the empirical data regarding human behavioural adaptation collected from field tests and driving simulator studies to mathematical models and implement them in traffic flow simulation platform. It is also recommended to develop automated lane change algorithms, taking into account connectivity between C/AVs which can be also implemented in driving simulators and traffic flow simulation platforms. Finally, it is recommended that future research investigate the combined effects of traffic safety and efficiency in designing DLs while considering driver behaviour adaptation and control transitions between manual and automated operation.