AUTOMATED HIGHWAY SYSTEMS (AHS) DESIGN FOR REAL WORLD IMPLEMENTATION: HOW DO WE GET THERE FROM HERE?

Major Automated Highway Systems (AHS) challenges concern building from existing highway infrastructures within affordable budgets, and applying AHS across various implementation locations. The authors have defined an integrated set of AHS concepts that provide a logical evolutionary path, and support implementation within urban and rural locations. The integrated AHS concept set contains three related concepts. They cover AHS evolution from initial deployment with low participation levels, to a mature nationwide AHS network; and work across the range of locations from high capacity urban to four lane intercity freeways. All three concepts treat vehicles as single entities organized and managed to satisfy safety, throughput, and lane access/egress requirements. When a lane is reserved for automated vehicles, the vehicle class specification includes a mass range (heaviest to lightest allowed) and a maximum width. Vehicles outside the class specification can operate in automated mode, but only on other lanes mixed with manual or partially automated vehicles. The three integrated concepts are called mixed flow, mixed transition lane, and dedicated flow. The mixed flow concept is suitable for all existing freeways, including rural four lane freeways, with few physical modifications required. It allows mixing of automated traffic together with manual or partially automated traffic. The mixed transition lane and dedicated flow concepts segregate AHS traffic on dedicated lanes, apply to freeways six lanes and wider, and require participation levels of 50% or greater. The dedicated flow concept applies when participation is large.