Roads present formidable barriers to dispersal. We examine movements of two highly mobile carnivores across the Ventura Freeway near Los Angeles, one of the busiest highways in the United States. The two species, bobcats and coyotes, can disappear from habitats isolated and fragmented by roads, and their ability to disperse across the Ventura Freeway tests the limits of vertebrates to overcome ...

The purpose of this study was to determine the influence of ramp spacing on the traffic flow characteristics on the Atlanta Freeway System and city streets influenced by the freeway. Timelapse photography was used to collect data at four study locations on the freeway. Speed and delay studies were also made on the freeway and surface streets during ramp closure periods and during normal operati...

The objective of this study was to assess the effectiveness of freeway lighting. To achieve this, a case study on traffic accident characteristics was conducted that utilized a suburban freeway area west of Frankfurt, Federal Republic of Germany, between 1972 and 1981. The study revealed that (a) the effects of lighting on suburban freeway accident rates was positive--there was a reduction in a...

Real-time traffic flow operation condition of freeway gradually becomes the critical information for the freeway users and managers. In fact, electronic toll collection (ETC) transaction data effectively records operational information of vehicles on freeway, which provides a new method to estimate the travel speed of freeway. First, the paper analyzed the structure of ETC transaction data and ...

Bottlenecks are key features of any freeway system and their impacts are of increasing importance as congestion worsens in urban areas. In Oregon, a freeway data archive known as PORTAL records measured count, occupancy, and speed data from over 600 locations at 20-second intervals. This archive has enabled development of online freeway performance and reliability analysis tools. This paper des...

This paper formulates the problem of real-time estimation of traffic state in freeway networks by means of particle filtering framework. A particle filter (PF) is developed based on a recently proposed speed-extended cell-transmission model of freeway traffic. The freeway is considered as a network of components representing different freeway stretches called segments. The evolution of the traf...

The California Freeway Performance Measurement System stores real-time data from 26,000 loop detectors. PeMS is accessed via an internet browser (http://pems.eecs.berkeley.edu/). It currently has 3 TB of data, growing at 2 GB/day. PeMS extracts useful information from these data and displays it in graphical or tabular form. These data provide an unparalled opportunity to assess freeway performa...

This paper aims to evaluate and compare the effects of different methods of ramp metering on the operational conditions of traffic flow at three levels: the network level (including the freeway and its connected ramps), the entrance ramp, and the upstream segment of the entrance. To achieve this aim, one of the most important urban freeways in the metropolis of Isfahan was selected. The traffic...

We develop a macroscopic model for mixed urban and freeway traffic networks that is particularly suited for control purposes. In particular, we use an extended version of the METANET traffic flow model to describe the evolution of the traffic flows in the freeway part of the network. For the urban network we propose a new model that is based on the Kashani model. Furthermore, we also describe t...