Realizing the problems that constantly accompany the use of road transport, against the background of the increasing shortage of liquid fuels of petroleum origin in Ukraine and other countries, serious attention has long been paid to the use of alternative, more environmentally friendly types of motor fuels, which include biofuels, natural gas and hydrogen. At the same time, the issue of reducing environmental pollution by road transport is an important component of the general environmental problem, the severity of which increases every year. With the significant growth of food industry facilities, there is a need to dispose of food products, namely food fats, which create a negative impact on the environment. Therefore, a possible way to solve the problem of disposal of edible fats can be their processing into diesel biofuel. The use of biodiesel fuel from recycled food fat waste does not require significant changes in the engine design, at the same time, it will allow to expand the fuel base of diesel vehicles and reduce their harmful impact on the environment. The article presents the results of bench tests of a passenger car with a diesel engine when operating on diesel fuel and diesel biofuel, namely: emissions of harmful substances and fuel consumption by cycle, comparative load characteristics of a diesel engine in a passenger car. The possibility of using diesel biofuel from recycled food fat waste in diesel engines of modern cars has been confirmed. The conducted studies proved the reduction of the total mass emissions, reduced to carbon monoxide emissions, for work on diesel biofuel. Keywords: diesel, diesel biofuel, passenger car, experimental tests, fuel consumption, harmful emissions.