Abstract
Keywords: Alternative fuels, CNG, city buses
Alternative fuels are defined as all fuels that can be used for motor vehicles apart from the gasoline and diesel fuel. The most popular alternative fuels at this moment are the gaseous fuels LPG and CNG, the alcohols ethanol and methanol and biodiesel. Natural gas is considered one of the most potential alternative fuels. The paper describes the basic types and characteristics of alternative fuels. The current state in the area of regulations concerning the exhaust emissions of diesel and gas engines is presented. An analysis is presented of various alternative vehicle technologies and some of the realized solutions of CNG city buses also presented. Particular attention has been dedicated to the problems and state of development of CNG city buses in our country.