 On 1 April 1992 it became an NHS Trust and served over 1.4 million people in an area of over .YAS operates just over 500 emergency vehicles which are a mix of Double Crewed Ambulances (DCAs), crewed by two members of staff (usually a qualified Paramedic or Emergency Medical Technician (EMT) working with an Emergency Care Assistant) and Rapid Response Vehicles (RRVs) which are crewed by a single paramedic, EMT or Emergency Care Practitioner.The emergency fleet is primarily made up of Mercedes Sprinter ambulances, Fiat ducato DCAs and Skoda Octavia rapid response vehicles.