One of the world's greatest challenges is the effort to reduce greenhouse gas emissions. One of the major sources of these emissions is road transport. The government is introducing a number of restrictions on the operation of internal combustion engine vehicles, such as a ban on warming up the engine. At the same time, car manufacturers are developing start–stop systems. All this is aimed at reducing fuel combustion and atmospheric emissions. Despite the complete phase-out of internal combustion engines by 2050, such vehicles will still form a significant part of the European car fleet. On the other hand, one of the reasons for the slow distribution of electric vehicles is their limited range. Both of these problems can be mitigated by energy-efficient driving. And how does the infrastructure of a city affect car operation and consequently fuel burn? The paper presents a mathematical model for energy-efficient control of connected highly automated vehicles in the conditions of the modern metropolis. The mathematical model incorporates terrain, speed modes, and traffic light schedules. Laboratory tests of the developed mathematical model are carried out on a digital twin of a test road section recreated on the basis of high-precision navigation data and a passenger vehicle with an internal combustion engine. In the laboratory tests, the proposed system is compared with a vehicle being driven on cruise control. The average speed of both vehicles on the selected route is identical. The results of the experimental runs indicate that the proposed mathematical model is 4.5% more efficient than the vehicle operating on cruise control. Further research is planned to adapt the developed model for hybrid and electric propulsion systems and to conduct field tests on unmanned vehicles with internal combustion engine and electric power plant.