The purpose of this work is to develop a multifactor mathematical model in Matlab Simulink environment, taking into account fuel consumption and a digital terrain model with variable inclinations of road surface with intersections and traffic light regulation, to conduct field experiments, as well as computer simulation and verification of the developed model. The paper proposes a mathematical model for calculating the instantaneous fuel consumption of a car with an internal combustion engine. The design of a digital twin of the car is described. A full-scale experimental run on a test road section is carried out, and the conditions of computer simulation are described. The results of calculation of instantaneous fuel consumption of the experimental car when driving on a test road section with elevation differences, controlled intersections, and different speed ranges are compared with the results of computer simulation. The results of computer simulation matched the field experiment by 98%. Conclusions are drawn about the applicability of the proposed approach to the process of development and verification of intelligent speed control algorithms for improving the energy efficiency of road vehicles.