Rethinking the main road design concepts for future Automated Vehicles Native Roads

Road design standards/guidelines are based on internationally valid concepts. They include requirements concerning alignment, sight distance, speed, friction, cross-sections. Those requirements are based on three main factors related to: drivers, physics, and comfort. The introduction of automated vehicles in the market will likely have a great impact on the road and transport design, management, operation and safety. In particular, the concept of road design and the related standards and guidelines may be modified, since some driver-based requirements may lose their significance in case of self-driving vehicles.In this article, basic International road design concepts are reviewed, with specific focus on rural roads. The review aims at classifying the design concepts into the three categories: driver-, physics-, and comfort-based. Based on this classification, the applicability of traditional road design concepts to Automated Vehicles Native Roads -AVNRs- (roads specifically designed for automated vehicles) is discussed, by also taking into account results from simulations performed for the possible design of AVNRs.As a result of the study, concepts/requirements concerning road design consistency and discrepancies between design, operating and posted speeds, may be not more necessary in case of AVNR design. Concepts/requirements related to tangent and curve lengths and sight distances may significantly change as well. Some minor modifications were discussed for cross-sectional elements (e.g. reduction of lane widths), and design speeds. The essentially physics-based design elements and requirements, such as curves, grades, road friction, sight distance (based on road geometry), transition curves and shoulders, should still be considered for the AVNR design instead, as well as comfort-based requirements.