Optimization of waiting time at toll plazas

Toll plazas have several toll payment types such as manual, automatic coin machines, electronic and mixed lanes. In places with high traffic flow, the presence of toll plaza causes a lot of traffic congestion; this creates a bottleneck for the traffic flow, unless the correct mix of payment types is in operation. The objective of this research is to determine the optimal lane configuration for the mix of the methods of payment so that the waiting time in the queue at the toll plaza is minimized. A queuing model representing the toll plaza system and a nonlinear integer program have been developed to determine the optimal mix. The numerical results show that the waiting time can be decreased at the toll plaza by changing the lane configuration. For the case study developed an improvement in the waiting time as high as 96.37 percent was noticed during the morning peak hour.

Development of a medium-capacity guideway transit planning guide

Rapid population increase and booming economic growth have caused a significant escalation in car ownership in many cities, leading to additional or, multiple traffic problems on congested roadways. The increase of automobiles is generating a significant amount of congestion and pollution in many cities. It has become necessary to find a solution to the ever worsening traffic problems in our cities. Building more roadways is nearly impossible due to the limitations of right-of-way in cities. Studies have shown that guideway transit could provide effective transportation and could stimulate land development. The Medium-Capacity Guideway Transit (MCGT) is one of the alternatives to solve this problem. The objective of this research was to better understand the characteristics of MCGT systems, to investigate the existing MCGT systems around the world and determine the main factors behind the planning of successful systems, and to develop a MCGT planning guide. The factors utilized in this study were determined and were analyzed using Excel. A MCGT Planning Guide was developed using Microsoft Visual Basic. ^ A MCGT was defined as a transit system whose capacity can carry up to 20,000 passengers per hour per direction (pphpd). The results shown that Light Rail Transit (LRT) is favored when peak hour demand is less than 13,000 pphpd. Automated People Mover (APM) is favored when the peak hour demand is more than 18,000 pphpd. APM systems could save up to three times the waiting time cost compared to that of the LRT. If comfort and convenience are important, then using an APM does make sense. However, if cost is the critical factor, then LRT will make more sense because it is reasonable service at a reasonable price. If travel time and safety (accident/crush) costs were included in calculating life-cycle “total” costs, the capital cost advantage of LRT disappeared and APM could become very competitive. The results also included a range of cost-performance criteria for MCGT systems that help planners, engineers, and decision-makers to select the most feasible system for their respective areas. ^

Business process quantitative analysis and optimization for service industries

The total time a customer spends in the business process system, called the customer cycle-time, is a major contributor to overall customer satisfaction. Business process analysts and designers are frequently asked to design process solutions with optimal performance. Simulation models have been very popular to quantitatively evaluate the business processes; however, simulation is time-consuming and it also requires extensive modeling experiences to develop simulation models. Moreover, simulation models neither provide recommendations nor yield optimal solutions for business process design. A queueing network model is a good analytical approach toward business process analysis and design, and can provide a useful abstraction of a business process. However, the existing queueing network models were developed based on telephone systems or applied to manufacturing processes in which machine servers dominate the system. In a business process, the servers are usually people. The characteristics of human servers should be taken into account by the queueing model, i.e. specialization and coordination. ^ The research described in this dissertation develops an open queueing network model to do a quick analysis of business processes. Additionally, optimization models are developed to provide optimal business process designs. The queueing network model extends and improves upon existing multi-class open-queueing network models (MOQN) so that the customer flow in the human-server oriented processes can be modeled. The optimization models help business process designers to find the optimal design of a business process with consideration of specialization and coordination. ^ The main findings of the research are, first, parallelization can reduce the cycle-time for those customer classes that require more than one parallel activity; however, the coordination time due to the parallelization overwhelms the savings from parallelization under the high utilization servers since the waiting time significantly increases, thus the cycle-time increases. Third, the level of industrial technology employed by a company and coordination time to mange the tasks have strongest impact on the business process design; as the level of industrial technology employed by the company is high; more division is required to improve the cycle-time; as the coordination time required is high; consolidation is required to improve the cycle-time. ^