Abstract
The deterministic analysis of queuing process tends to yield unrealistic results due to the stochastic nature of the system in
reality. This study carried out a stochastic analysis of queuing process at the Nigerian National Petroleum Corporation
(NNPC) filling station situated at Nyanya area along Karu road and the AYM Shafa filling station located at Gudu District,
Apo in the Federal Capital Territory (FCT) Abuja using SimEvent toolkit of Simulink in Matrix Laboratory (MATLAB)
software. Queuing characteristics such as arrival rate, service time, queue length, waiting time and utilisation fa ctor were
examined using simulation model based on empirical results obtained from field surveys. Results obtained from the stochastic
analysis revealed that; average inter-arrival time at the stations were 1.11 min/veh and 1.18 min/veh, while average inte rservice
times were 0.98 min/veh and 1.10 min/veh for the NNPC and AYM Shafa filling stations respectively. There was no
noticeable waiting time and queue length at both stations. Outputs of the simulation model performed more realistically since
they indicated variations with time which depicted the real behaviour of queuing systems, hence could be used for
investigating system performance over time. The SimEvents toolkit was recommended for managers of queuing systems to aid
in decision making and operational policies for improved services.

Key words: Deterministic analysis, Stochastic analysis, Queuing process, SimEvents toolkit