conference paper
published journal article
published journal article
conference paper
conference paper
Development of advanced technologies for real-time road traffic congestion detection is required by advanced traffic management systems (ATMS) and advanced traveler information systems (ATIS). However, provision of dynamic intra-lane and inter-lane traffic information such as queuing and lane-changing remains incomplete in emerging technologies. This paper is intended to introduce a prototype of a new framework capable of real-time detection of incident and non-incident congestion on freeways. It employs dynamic estimates of lane traffic characteristics including queue lengths in blocked lanes tin the case of lane-blocking incidents), the number of vehicle in each lane, and mandatory lane-changing fractions in lanes with traffic congestion for the use of real-time road traffic congestion detection. On-line lane traffic count and occupancy data collected from point detectors are used as the major input to the proposed framework. The framework is founded on the basis of 1) nonlinear stochastic system modeling and estimation which involves the use of an extended Kalman filter and 2) the modified sequential probability ratio test technology (MSPRT). Preliminary tests had been conducted, indicating the feasibility of employing the proposed framework for the use in real-time incident detection on freeways. Further tasks will include tests for the case of non-incident congestion. The research presented here may help stimulate research in related areas such as incident management systems, automatic vehicle tracking and monitoring systems, and automatic road congestion warning systems for further use in ATMS and ATIS.
working paper
The growth of the Internet has rekindled interest in the relationship between communications and travel. New communication technologies have expanded the range, the type, and the number of transactions that can take place without travel. A number of promotions capture the new tradeoffs between communications and travel: initially, the Internet was referred to as “the information superhighway” and Microsoft ran an ad campaign dubbed “where do you want to go today?” The connection between travel and bytes has been summed up as “The Death of Distance” (Cairncross, 1997). A parallel evolution in telecommunication and transportation was envisioned more than 150 years ago with the inventions of the telegraph and telephone. The telephone was expected to “speed the movement of perishable goods,” “reduce the travels of salesmen,” and “let (itinerant) workers stay at home to be phoned for jobs” (Pool, 1983). Today, the Internet has fueled similar expectations, and many of them center on travelrelated issues. The Internet might relieve demand for new road capacity, slow down the rate of new vehicle ownership, and divert existing travel trips to less congested times. The Internet might help create more sustainable growth in transportation, by providing virtual accessibility. In this paper, we explore the transportation aspects of consumer electronic commerce (e-commerce). Shopping activities are currently automobileintensive in many countries, and increases in e-commerce could portend important changes in transportation patterns and activities.
conference paper
published journal article
published journal article
Discretionary grant programs have been popular with state legislatures as a mechanism for extending the benefits of transit programs to small cities and rural areas as well as for stimulating innovations in urban areas. This article analyzes state discretionary grant transit programs in California and Minnesota by using the criterion of effective administration. The purpose is to develop a framework for understanding administrative problems that result when state discretionary transit programs do not have adequate objectives. Without explicit objectives, selection, monitoring, evaluation, and overall management are weak. Project performance is reduced and scarce public funds are wasted. Recommendations include the following: (a) legislatures should make explicit the mission and goals of discretionary programs, (b) administrative agencies should define measurable objectives and administrative guidelines, and (c) local grant recipients should be granted funds only after specific objectives and performance standards have been presented.
book/book chapter
Transportation policy making often requires evaluating a proposed discrete change, whether it be a physical investment or a new set of operating rules. Some proposals, like the rail tunnel under the English channel, are one-time capital investments with long-lasting effects. Others, like congestion pricing proposed for The Netherlands, require major behavioral and political groundwork.
conference paper |
Dec 2000
working paper |
Oct 1993
