Emergency vehicle maneuvers and control laws for automated highway systems

In this thesis, the problem of high priority transit for emergency vehicles (EV) on automated highway system (AHS) is investigated. The goal of the EV maneuvers and control laws presented in this thesis is to ensure that EVs travel faster than the nominal AHS traffic in the same highway section in free-flowing traffic conditions. It is assumed that all AHS vehicles are fully automated and that there are no highway shoulders. Both individual vehicle maneuvers and mesoscopic traffic flow maneuvers are needed to maintain this region of low vehicle density around the faster moving EV.; The hierarchical control architecture introduced by California Partners for Automated Transit and Highways (PATH) is used to separate the complex problem of controlling all AHS vehicles into five smaller control layers. The main contribution of this thesis is the development of EV specific control laws and maneuvers for the link and coordination layers of the PATH hierarchical control architecture.; At the link layer, individual vehicles are not identified or controlled; traffic is treated as a continuum. For low traffic density conditions, a traffic flow control law, nicknamed the Bubble maneuver in this thesis, is presented which enables the vehicle flow in one lane to be circulated out of the way of the section in which the fast moving EV travels. The Bubble maneuver only uses lane changing commands to achieve this circulation. Another traffic flow control law, nicknamed the Volcano maneuver in this thesis, is developed for high traffic density conditions. The Volcano maneuver requires both traffic flow speed changes and lane changing commands. To achieve the traffic flow speed changes, traffic flow velocity must be varied in a specific way; the idea of a non-stationary velocity profile is introduced. Two link layer stabilizing controllers are developed specifically for accommodating non-stationary velocity profiles.; For the coordination layer, this thesis evaluates the previously designed Vortex maneuver, which microscopically moves individual vehicles out of the way of an EV. The Vortex maneuver is found to be inadequate because it does not reestablish the original configuration of vehicles after the EV has passed. A new and improved Vortex2 maneuver, which does reestablish the position of vehicles, is designed and tested.