 California defines a ULEV as a vehicle that has been verified by the California Air Resources Board (CARB), United States to emit 50% less polluting emissions than the average for new cars released in that model year.Under LEV II regulations, the Tier I and TLEV classifications were removed for 2004.The ULEV is one of a number of designations given by the CARB to signify the level of emissions that car-buyers can expect their new vehicle to produce and forms part of a whole range of designations, listed here in order of decreasing emissions