Despite the development of multilane free flow (MLFF) tolling solutions, a large number of toll road projects with a barrier toll collection system (TCS) are currently being implemented in Russia. Therefore, studies of toll
plazas (TP), as a transport infrastructure element of barrier TCS, are still relevant. Ignoring issues of assessing current and predicted intensity on TPs can cause regular traffic congestions on toll roads. This study
addresses the issue of TP assessment throughput capacity during toll road operational stage. We use discrete-event simulation of TP. As a methodology for transport micro-modeling Western High Speed Diameter toll road TP
in St. Petersburg, Russia, was considered as a case for our study. The simulation model of TP at the exit of toll road was developed with the help of AnyLogic software. We accounted for the specifics of traffic composition
and user behavior in the selected urban district. Traffic intensity value of forming traffic congestion at TP was established experimentally. We analyzed two cases of service time distribution with low and high traffic
intensity. In the first case, our results show a splitting of total service time distribution into two distributions for different toll lane operating modes. In the second case, influence of user behavior on nature of the
TP service time distribution was revealed. For both cases we determined parameters of gamma laws for service time distribution. Our findings indicate that when TP throughput capacity is insufficient, TP performance becomes
low, and service time distribution increases, regardless of the type of fare payment. Implications for toll road operators and useful insights are discussed.