The problem of numerical estimation of the functionals of the solutions to a Boltzmann type nonlinear equation in the kinetic model of a vehicle traffic flow with separated acceleration is considered. The authors construct a second-kind integral equation for the original probabilistic model of a vehicle traffic flow, which is related to a linear N-particle model of the vehicle system evolution. Weighted Monte Carlo methods are proposed for the estimation of the functionals of the solution to the obtained equation. The practical suitability of this approach to the solution of traffic problems is demonstrated by numerical experiments. It should be noted that, in contrast to the previous papers, the authors do not use an artificial time step not included in the original traffic flow model.This paper is focused on the study and simulation of a vehicular traffic flow (VTF). The urgency of this problem is related to the permanent growth of the vehicular traffic. This leads to the necessity to improve the traffic system taking into account the mechanisms of its development and the load distribution of its segments.Researchers from different scientific areas have been involved in the study of traffic systems, and now we have voluminous literature concerning the study and simulation of VTF. Two basic approaches have been formed historically in modelling of the vehicular traffic: the deterministic and probabilistic ones. Deterministic models are based on a functional dependence between particular parameters, for example, the velocity and the distance between the vehicles in the flow. Stochastic models of VTF are considered as a probabilistic process. In addition, all models can be divided into three classes: micro-, macro-, and mesoscale ones.Microscope models (e.g., leader-following model [1], cellular automata [10]) use motion equations similar to Newtonian ones written separately for each particle in the system of interacting particles. The driver's behaviour in the models of such type is described by deterministic parameters, or by random functions.Macroscope models (e.g. the Lighthill-Whitham model [7]) simulate the VTF by a flow of a one-dimensional compressible fluid. It is assumed in this case that the flow is preserved (this condition is expressed by the continuity equation) and there exists a one-to-one correspondence between the intensity (or mean velocity) and the density of the VTF.