An algorithm for real time estimation of truck traffic in multi-lane freeway is proposed. The algorithm uses data from single loop detectors—the most widely installed surveillance technology for urban freeways in the US. The algorithm works for those freeway locations that have a truck-free lane, and exhibit high lane-to-lane speed correlation. These conditions are met by most urban freeway loc...

roundabouts, intersections, bridges, and work zones. A 1995 review of current practice by Griffin and Reinhardt showed rather extensive experimentation with transverse-bar markings throughout the United States (1). Several patterns, colors, sizes, and spacings had been reported for the various transverse-bar installations, with widely inconclusive results on their effectiveness for speed reduct...

Traffic flow theory is used to analyze the spatio-temporal distribution of flow and density on closedloop homogeneous freeways with many ramps, which produce inflows and allow outflows. It is shown that if the on-ramp demand is space-independent then this distribution tends toward uniformity in space if the freeway is either: (i) uncongested; or (ii) congested with queues on its on-ramps and en...

The paper introduces a new understanding of freeway capacity. Here capacity is understood as the traffic volume below which traffic still flows and above which the flow breaks down into stop-and-go or even standing traffic. It is easy to understand that a capacity in this sense is by no means a constant value. Empirical analysis of traffic flow patterns, counted at 5minute intervals over severa...

Computing and information technology has significantly increased the capabilities to collect, store, and analyze freeway traffic surveillance data. The most common forms of such data are collected using the underground loop detectors. In the recent past the potential of using these data for identification of crash-prone conditions has been explored. In the present work, application of probabili...

Text messaging while driving can be distracting and significantly increases the risk of being involved in a collision. Compared to freeway driving, driving in a tunnel environment introduces factors that may interact with driver attentional resources to exacerbate the effects of distraction on driving safety. With planning and design of the 18km Stockholm Bypass tunnel ongoing, and because of t...

We measured the spatial pattern of particle number (PN) concentrations downwind from the Los Angeles International Airport (LAX) with an instrumented vehicle that enabled us to cover larger areas than allowed by traditional stationary measurements. LAX emissions adversely impacted air quality much farther than reported in previous airport studies. We measured at least a 2-fold increase in PN co...

We consider coordinated traffic control for networks consisting of both urban roads and freeways. One of the main problems that has to be addressed when designing traffic control strategies for such networks is that we should prevent a shift of problems from the urban network to the freeway network (or vice versa) due to the applied control strategy. First, we develop an integrated model to des...

Background. Proximity to heavy traffic has been linked to increased asthma severity. However, it is unknown whether exposure to heavy traffic is associated with the ability to maintain asthma control. Objectives. This study examines whether exposure to heavy traffic is associated with the ability to maintain asthma control in inner-city children. Methods. 756 inner-city asthmatic Hispanic child...

On-ramp merging areas are essential parts of freeways. The behavior vehicles is the main factor affecting continuity freeway traffic flow, which determines capacity line. With development innovative car technology, ACC technology has been widely used in actual vehicles. At same time, public’s demand for freeway-speed improvement increasing. However, evaluative research on freeway-speed-improvem...