17-01 An Intersection Database Enhances Blind Pedestrians\u27 Access to Complex Signalized Intersections: Stage 2 Analysis & Database Development

This project investigated the effects of providing verbal descriptions of intersections and crosswalks on the performance of street-crossing subtasks by individuals who are totally blind. The intersections included crosswalks that varied widely in geometric and operational characteristics, including the presence or absence of accessibility features. In the no-database condition, participants used their typical street-crossing procedures. In the database-condition, participants additionally listened to database-generated descriptions of the intersections and crosswalks before crossing. The database descriptions had significant positive effects on some subtasks (primarily “crossing” subtasks such as deciding when to cross) and not others (primarily “wayfinding” subtasks such as remaining in the crosswalk)

Roundabout accident prediction model: random-parameter negative binomial approach

Roundabouts have been used widely on all road classes in the United Kingdom because they are considered safer than other types of intersections in general. The objective of this study was to examine geometric and traffic characteristics and their influences on the number of accidents. Data from each of 70 roundabouts (with 284 approaches) included all recorded vehicle accidents as well as geometric and traffic characteristics for the entire roundabout, within circulatory lanes, and at roundabout approaches. Resulting estimates were compared with those from random-parameter and fixed-parameter negative binomial count data models. The random-parameter results provided better goodness of fit than the fixed-parameter results, and more variables were found to be significant. Significant variables that influenced the number of accidents were total approach traffic, truck percentage, entry width, inscribed circle diameter, number of lanes, and presence of traffic signals

Interaction between motor vehicles and bicycles at two-lane roundabouts: a driving volatility-based analysis

Drivers' instantaneous decisions regarding speed and acceleration/deceleration, as well as the time rate of acceleration change (jerk) can result in a volatility driving behaviour with significant impact on cyclist safety. The contribution of this article is the assessment of driving volatility in motor vehicle (MV)-bicycle interactions at two-lane roundabouts. Traffic flow and bicycle GPS data were collected from two two-lane roundabouts. Then, traffic, emissions and safety models were used to evaluate volatility impacts on safety, pollutant emissions and traffic performance. The findings showed jerk have an impact on driving volatility between MVs and bicycles, regardless of roundabout design with higher amplitude of variation for MVs. However, MVs had higher acceleration-deceleration variation than bicycles.publishe

Biological Effects and Safety in Magnetic Resonance Imaging: A Review

Since the introduction of Magnetic Resonance Imaging (MRI) as a diagnostic technique, the number of people exposed to electromagnetic fields (EMF) has increased dramatically. In this review, based on the results of a pioneer study showing in vitro and in vivo genotoxic effects of MRI scans, we report an updated survey about the effects of non-ionizing EMF employed in MRI, relevant for patients’ and workers’ safety. While the whole data does not confirm a risk hypothesis, it suggests a need for further studies and prudent use in order to avoid unnecessary examinations, according to the precautionary principle

Comparison of traffic signal system timing policies using stochastic simulation

M.S.John D. Leonard, I

Roundabout operations : a summary of FHWA's - 'Roundabouts: An Informational Guide'

Paper presented at the 20th Annual South African Transport Conference 16 - 20 July 2001 "Meeting the transport challenges in Southern Africa", CSIR International Convention Centre, Pretoria, South Africa. ABSTRACT: As in many other countries, roundabouts are receiving renewed interest in South Africa.The Federal Highway Administration (FHWA)publication, 'Roundabouts: An Informational Guide', presents a comprehensive discussion of roundabout planning, performance analysis, and design. No specific local guidelines for roundabouts have been developed and local engineers rely mostly on English and Australian methods. This guide provides another useful tool for the traffic engineering toolbox. One of its features is the definition of six categories of roundabouts, ranging from small, urban mini-roundabouts to relatively large, rural double-lane roundabouts. Distinctions have been made between the various categories in terms of characteristics, planning procedures, operational analysis, and design treatments. This paper presents the various elements of operational analysis included in the guide, including measures of capacity and performance analysis,and provides a discussion of many of the decisions made during the development of the guide. The paper presents capacity curves for urban compact roundabouts, single-lane roundabouts, and double-lane roundabouts, as well as adjustment factors to account for the effect of short lanes (flaring). The paper also presents the methodologies and recommended practices for determining degree of saturation, delay, and queuing.This paper was transferred from the original CD ROM created for this conference. The material on the CD ROM was published using Adobe Acrobat technology. The original CD ROM was produced by Document Transformation Technologies Postal Address: PO Box 560 Irene 0062 South Africa. Tel.: +27 12 667 2074 Fax: +27 12 667 2766 E-mail: [email protected] URL: http://www.doctech.co.z