The agro-industrial complex is a stable consumer of mobile means of mechanization in a wide variety of industry activities almost every day and around the clock. This is required by various types of life, dictated by the specifics of production (livestock, poultry, horticulture, open and closed ground, storage, processing and sale, etc.). The needs of production are characterized by a variety of units, the prevailing of which are tractors, automobiles, harvesters. All of them are powered by combustion engines and transmissions with different numbers of gears. The frequency of using the latter is dictated by the type of work and their technology. The practice of using such units is characterized by their frequent installation and engine shutdown (technological and technical failures, technological needs, breaks, etc.). The operating requirements provide for the fixation of the units when parked with a hand brake and a gear engaged, excluding spontaneous rolling due to the relief of wind loads, etc. when diesels are started by starting engines and when operators are between the front and rear wheels. Such assaults usually end in severe or fatal outcomes, the number of which in the agro-industrial complex is averaged about 45 people annually. In order to exclude such a situation, an innovative locking device has been proposed that excludes automatically stated situations and related injuries. The performance of the device has been confirmed by laboratory tests.