This thesis describes research carried out to investigate and model toll system operations on a closed toll highway network in Malaysia. The main objectives were to identify factors that influence toll oeprations and to investigate the effect of alternative layouts and strategies on toll system operations. Field surveys were conducated at the Sungai Besi toll plaza near Kuala Lumpur and teh Senai toll plaza near Johor Bahru. Field data included parameters such as trafffic flow, composition, headway adn speed distributuions that are the demand elements to the toll system and the plaza layout, numbet of toll booths and of the system. Drivers' booth selection behaviour and while drivers follow each other very closely on the highway they take a relatively long time to move-up into service when in queue at the toll booths. A microscopic time scanning simulation model tat describes traffic behaviour in a toll system has been developed. The model deals with the following toll operations strategies : closed and opened toll systems, different toll collection systems and multiple toll systems. The mdoel has been calibrated and validated by comparing measures of delay and throughout with data obtained at the Sungai Besi toll plaza over several peak and off-peak periofd. The mdoel has also been appleid to examine the impact of introducing automatic vehicle identification (AVI) in the toolng system. The results show that the number of AVI booths provided ahould be limited to a certain number when the percentage of vehicles using the AVI system is less then or equal to sixty percent. A multiple toll situation commonly found at border entries was also examined. The results show that buffer distances will affect vehicle delays and that an optimum buffer distance will result in minimum delays. A proposal has been forwarded for the construction of toll design charts by exploiting the advantages of simulation modelling embodied in the model developed.