Towards a realistic microscopic description of highway traffic

Simple cellular automata models are able to reproduce the basic properties of highway traffic. The comparison with empirical data for microscopic quantities requires a more detailed description of the elementary dynamics. Based on existing cellular automata models we propose an improved discrete model incorporating anticipation effects, reduced acceleration capabilities and an enhanced interaction horizon for braking. The modified model is able to reproduce the three phases (free-flow, synchronized, and stop-and-go) observed in real traffic. Furthermore we find a good agreement with detailed empirical single-vehicle data in all phases.Comment: 7 pages, 7 figure

Safety Data: Costs, Quality and Strategies for Improvement- Executive Summary

FHWA-RD-96-027The objectives of this project were to examine the costs and quality of safety data and to identify improvement strategies. The project's scope was narrowed to three key sources: the crash report, roadway inventories, and medical records. The primary focus was on crash reporting. Within the medical source, the focus was upon data regarding driver condition prior to crash, and injury severity, since these are of high interest to the highway community. Since the same piece of data will have a different quality for different users and uses, it was necessary to identify the variety of users and uses of highway safety data. This executive summary presents an overview of the research results. The complete results are available in the research report (FHWA-RD-96-191) and the final report (FHWA-RD-96-192)

An Overview of Three Promising Mechanical, Optical, and Biochemical Engineering Approaches to Improve Selective Photothermolysis of Refractory Port Wine Stains

During the last three decades, several laser systems, ancillary technologies, and treatment modalities have been developed for the treatment of port wine stains (PWSs). However, approximately half of the PWS patient population responds suboptimally to laser treatment. Consequently, novel treatment modalities and therapeutic techniques/strategies are required to improve PWS treatment efficacy. This overview therefore focuses on three distinct experimental approaches for the optimization of PWS laser treatment. The approaches are addressed from the perspective of mechanical engineering (the use of local hypobaric pressure to induce vasodilation in the laser-irradiated dermal microcirculation), optical engineering (laser-speckle imaging of post-treatment flow in laser-treated PWS skin), and biochemical engineering (light- and heat-activatable liposomal drug delivery systems to enhance the extent of post-irradiation vascular occlusion)

Development of performance measures for police traffic services - phase 1. Final report.

National Highway Traffic Safety Administration, Washington, D.C.Mode of access: Internet.Author corporate affiliation: Northwestern University, Evanston, Traffic Institute, Ill.Cover date is April 1984Subject code: FICBSubject code: HCESubject code: WW