A methodological framework is formulated so that continuum approximation techniques can be used to design bus networks for cities where travel demand varies gradually over space. The bus-route configurations that result consist of (i) a main, possibly city-wide grid with relatively large...

A recent study (Li and Ouyang, 2011) proposed a describing-function approach (DFA) to analytically predict oscillation propagation properties (i.e., dominating frequency and amplitude growth) for a general class of nonlinear car-following laws. This paper presents a new graphic solution approach...

This paper presents an analytical approach for joint planning of pavement maintenance and resurfacing activities that minimizes pavement lifecycle costs, including user, maintenance and resurfacing costs, for an infinite time horizon. The optimization problem is formulated as a nonlinear...

Unlike linear car-following models, nonlinear models generally can generate more realistic traffic oscillation phenomenon, but nonlinearity makes analytical quantification of oscillation characteristics (e.g, periodicity and amplitude) significantly more difficult. This paper proposes a novel...

This paper presents mathematical models that optimize the size of transportation fleet (cranes and trucks) for unloading operations at container terminals. A cyclic queue model is used to study the steady-state port throughput, which then yields the optimum fleet size for long-term operations....

This paper proposes algorithms to automatically discretize vehicle routing zones (VRZ) from continuum approximation guidelines. VRZs that satisfy these guidelines (i.e., shape and size requirements) are useful to the planning and operation of distribution systems in several practical contexts....

This paper presents an analytical approach for planning highway pavement resurfacing activities in the case of continuous pavement state and continuous time. It solves for the optimal resurfacing frequency and intensity that minimize life-cycle costs in a finite horizon. Optimality conditions...

US railroad companies spend billions of dollars every year on track maintenance in order to ensure safety and operational efficiency. Optimizing the production team (i.e., large maintenance team) schedule is a very complex problem with major cost implications. In current practice, the decision...

Railroad companies spend billions of dollars each year to purchase fuel for thousands of locomotives across the railroad network. Each fuel station charges a site-dependent fuel price, and the railroad companies must pay an additional flat contracting fee in order to use it. This paper presents...

This research focuses on planning biofuel refinery locations where the total system cost for refinery investment, feedstock and product transportation and public travel is minimized. Shipment routing of both feedstock and product in the biofuel supply chain and the resulting traffic congestion...