3. Conclusion and Future Research
In this project we studied several design problems in toll plaza systems. This problem is
important to the overall transportation infrastructure to the nation in general, and to the state of
New Jersey in particular. Clearly, there are many interesting research work remain to be done.
The first one is a simulation software that incorporates user friendly interfaces with animation
capabilities. The success of such a simulation software relies heavily on the understanding of the
behavior of drivers. The usefulness of such a software is clear, it will enable use to test different
designs on the computer screen, and convince the transportation officials to adopt these designs.
Another research issue that needs to be addressed is, as we have already showed, a good design
depends on our understanding of vehicle delays for each type. Even though we can calculate the
vehicle delays by simulation, and qualitative understanding is not easy to obtain only through
simulation, even if the simulation is not expensive to run at all. Thus, some analytical results for
the delays for each type of vehicles in terms of traffic intensities are desired. Such analytical
results will be extremely important and will play significant roles in identifying a good design.
On the other hand, as we explained earlier, even in the simplest case the resulting queueing
problem is not analytically tractable. The only remaining resort is to develop approximation
formulas for the delays. Once these approximations results are obtained, they can be used in
determining the number of each type of tollbooths as well as at different times of the day, of the
week, and of the month. The design should be given in the form of a chart, which instructs the
specific design at any given period of time of the day, e.g., 7:30am-8:30am, Monday, or 10:00am
– noon, Saturday, etc.