We address the problem of shockwave formation in uncoordinated highway traffic. The problem is caused by the combination of heavy traffic and small traffic perturbations or unexpected drivers actions. We propose a novel distributed communication protocol that helps mitigate upstream shockwave formation even with extremely low system penetration rates. Based on traffic information ahead, the Cooperative Advanced Driver Assistance System (CADAS) recommends non-intuitive velocity reductions in order to redistribute traffic more uniformly and eliminate traffic peaks. Simulation results show...
In recent years, technological and social forces have pushed smartphone applications (apps) from the fringe to the mainstream. Understanding the role of transportation apps in urban mobility is important for policy development and transportation planners. This study evaluates the role and impact of multimodal aggregators from a variety of perspectives, including a literature review; a review of the most innovative, disruptive, and highest-rated transportation apps; interviews with experts in the industry, and a user survey of former multimodal aggregator RideScout users. Between February...
Time-dependent shortest path problems arise in a variety of applications; e.g., dynamic traffic assignment (DTA), network control, automobile driver guidance, ship routing and airplane dispatching. In the majority of cases one seeks the cheapest (least generalized cost) or quickest route between an origin and a destination for a given time of departure. This is the "forward" shortest path problem. In some applications, however, e.g., when dispatching airplanes from airports and in DTA versions of the "morning commute problem", one seeks the cheapest or quickest routes for a given arrival...
This paper presents early findings from an application of advanced parking technologies to increase effective parking capacity at a transit station during the first half of 2004 in the San Francisco Bay Area (CA). It begins with an extensive review of the literature related to transit-based smart parking management systems to illustrate the range of system configurations and their potential travel, economic, and environmental effects. Two important conclusions from this review are: (1) lack of parking spaces at transit stations may be a significant constraint to transit use and (2) pre-...
California Partners for Advanced Transit and Highways has teamed with the California Department of Transportation, the Bay Area Rapid Transit (BART) District, ParkingCarmaTM, and Quixote Corporation to launch a smart parking research demonstration at the Rockridge BART station in the East San Francisco Bay Area (California, USA). The results of an extensive literature review demonstrate that different smart parking applications implemented worldwide can ease traveler delays, increase transit ridership, and reduce operator costs. Observational analyses at the station indicated that existing...
This study examines the extent to which states have devolved one of the most fundamental decisions in transportation policy—whether to use taxation powers to fund transportation improvements—to local and regional governments. The purpose of the study is to generate a baseline of knowledge on “local option transportation taxes” in all fifty states, including the relevant legislative authority for these taxes, the extent to which local areas have adopted them, and the roles they play within their states’ overall transportation finance frameworks.
Freeway on-ramp metering (RM) has been extensively used as a traffic control strategy to regulate the entry of the on-ramp vehicles to prevent congestion at the freeway merging areas and preserve the freeway capacity. Benefits of RM include improved freeway travel times, improved travel time reliability, and accident reductions. Fixed-rate ramp metering strategies are based on historical data and implemented by time of day. Traffic responsive RM strategies are based on real time freeway traffic data provided by loop detectors at the vicinity of the on-ramp. Coordinated RM determine the...
This research project directly addresses the Caltrans policy question of “How to meet the SB 1 ten-year (2027) mandated preliminary performance outcomes for additional state highway investments?” More specifically, the study focuses on performance outcome number 4: “Not less than 90 percent of the transportation management system units in good condition”. As part of this project, the research team evaluated the Caltrans performance-based methodology to achieve the 90% performance goal in addition to completing a review of relevant reports from the Federal Highway Administration (FHWA),...
Intelligent transportation systems and technology provide a high return on investment, especially when incorporated as part of ongoing construction activities. Efficient operation and maintenance of our transportation infrastructure requires real time data exchange provided by ITS (Intelligent Transportation System) technology. The cost to acquire and install this technology is roughly 5% of the overall construction budget if installed during construction. The ROI (measured in safety, travel time reliability, throughput and quality of life) takes less than 6 months in highly congested...
In recent years, “smart city” information and communication technologies have proliferated. For local government agencies, procuring and introducing these technologies offers the possibility to manage infrastructure assets more effectively, plan for preventive maintenance, and disseminate schedules and information about transit and other services. Many of these technologies are deployed by private firms in the context of local regulations and government-sponsored incentives. In the transportation sector, examples of “smart city” technology services provided by private firms include:...
