The Port Authority of New York and New Jersey is set to begin testing three models of self-driving electric vehicles at Newark Liberty International Airport in spring. The tests will involve zero-emissions vehicles from autonomous-tech companies Oceaneering, Ohmio and Glydways. The testing will qualify these companies for a formal request for proposals, which could be issued as soon as next year. The Port Authority has previously conducted similar self-vehments at John F. Kennedy International Airport and has also tested autonomous lane-keeping technology on buses in its exclusive bus lane in the Lincoln Tunnel.