877 research outputs found
Microscopic Modeling of Traffic Within Freeway Lanes
No full textMicroscopic models provide an understanding of traffic operations at the level of passage of individual vehicles. Roadway performance can be ascertained by understanding how vehicles interact with each other. Cowan's M3 headway distribution models were calibrated for the curb and median lanes of two-lane mainline freeway segments, using data captured at 14 sites. Calibration of the relationship among Cowamn's M3 parameters, proportion of headways greater than a minimum of 1 sec, and flow rate yielded exponential decay equations for each lane. The M3 models provide a source of vehicle arrivals for gap acceptance models, which may be used to quantify the ability of drivers to change lanes, for example. It was found that the parameters calibrated for each lane are suitable for use at any mainline site, independent of site-specific conditions. The proportion of small headways was found to be higher in the median lane than the curb, for all flow rates, and for both lanes lower than their respective equivalents on arterial roads with intersections. The largest bunched headway was considered to be between 2 and 3 sec. The models predicted bunching between 85 and 93 percent of median lane vehicles, and between 75 and 90 percent of curb lane vehicles, at capacity. The lesser amount of curb lane bunching reflects its use as a slower vehicle lane with greater stream friction
The Annual Walter Rodney Symposium, 2022
No full textThe 19th Annual Walter Rodney Symposium titled "Walter Rodney: 50 Years of How Europe Underdeveloped Africa" took place on Saturday, March 26th, 2022 from 10:00am - 3:00pm EST. The virtual conference featured keynote speaker Dr. Joyce Ladner who highlights her relationship with Dr. Walter Rodney. The panel hosted by Kurt B. Young featured Dr. Horace G. Campbell, Professor Issa Shivji, and Walter Bgoya, and discusses the work of Walter Rodney and Julius Nyerere. The panel hosted by Zophia Edwards featured a lecture by Dr. Vijay Prashad and respondents Natasha Shivji, Tamnisha John, Kamau Franklin, and Cindy Peters about the text "How Europe Undeveloped Africa". There were Q & A segments and global remembrances. The 2022 symposium was co-hosted by The Walter Rodney Foundation and the AUC Woodruff Library
Development of a flexible design approach for the deflection zone behind road safety barriers
No full textFlexible design practices broadly permit that design values outside the normal range can be accepted as appropriate for a site-specific context providing that the risk is evaluated and is tolerable. Execution of flexible design demands some evaluation of risk. In restoration projects, it may be the case that an immovable object exists within the zone of the expected deflection of a road safety barrier system. Only by design exception can the situation be determined to be acceptable. However, the notion of using flexible design for road safety barrier design is not well developed. The existence of a diminishing return relationship between safety benefits and provision of increased clear zone has been established previously. This paper proposes that a similar rationale might reasonably apply for the deflection zone behind road safety barriers and describes how the risk associated with road safety barriers might be quantified in order that defensible road safety barrier design can exist below the lower bounds of normal design standards. As such, the methodology described in this paper may provide some basis to enable road authorities to make informed design decisions, particularly for restoration, or “Brownfield”, projects
Moving Towards Smart Compliance - Using GPS to Monitor Large Special-Combination Vehicles
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Effect of restriction of vision on driving performance
No full textThe effect of restricting vision on driving performance was investigated\ud
in a field study. Commonly occurring binocular visual-field defects were\ud
simulated for a group of young normal subjects and the effect of these defects on\ud
their driving performance on a private closed rural road, free of other vehicles,\ud
was assessed, The monocular condition did not significantly affect performance for\ud
any of the driving tasks assessed. Restriction of the binocular visual field to 40 ~\ud
and less, significantly increased the time taken to complete the course, reduced\ud
the ability to detect and correctly identify road signs, avoid obstacles, and to\ud
maneuver through limited spaces. Accuracy of road positioning and reversing were\ud
also impaired with field restriction. However, the time taken for many driving\ud
tasks, reversing and maneuvering, and the driver's ability to estimate speed, stopping\ud
distance, or reaction time were not affected by a restriction of the binocular\ud
visual fields. The results are discussed with regard to their impact on traffic engineering practices
Zero roadworker harm: Ethical and legal challenges
No full textGovernments are required to make difficult decisions, requiring policymakers to strike a balance between equity for individuals and the collective good. Specifically with regard to road safety at roadworks, policymakers must find an acceptable balance between cost, mobility and the safety of both road users and workers. Discussion of the ethical and legislative challenges associated with finding such a balance is largely absent from the Australian road safety context. By means of review and reflection relating to literature, policy and legislation, this paper explores aspects of governmental intervention and management of risk through the general lens of road safety ethics and regulation of the road network. More specifically, this paper presents a discussion of the ethical, legislative and economic challenges confronting practitioners required to select positive protection for roadside work zones in Queensland, Australia. The ‘so far as is reasonably practicable’ principle is explored for consistency both with legislation governing the management of road infrastructure and with governmental commitments to achieve zero harm. This paper concludes that disconnects exist between requirements for practitioners to manage the road efficiently and requirements for practitioners to provide a workplace that is ‘safe’
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