scholarly journals Analysis of Gap Patterns in Longitudinal Rumble Strips to Accommodate Bicycle Travel

Author(s):  
Richard C. Moeur

Rumble strips can offer significant reductions in run-off-road crashes on rural highways. Newer ground-in rumble strip designs can be installed on a wider variety of shoulders, but these new designs have a much greater negative effect on bicycle traffic than did previous designs. The feasibility of placing gaps in a rumble strip pattern to permit bicycle traffic to cross the rumble strip area without striking the rumble strip pattern itself was investigated. A recommended minimum length for these gaps to accommodate bicyclists of varying abilities at speeds representative of downhill conditions was also determined. On the basis of experimental information collected, the researchers recommend that rumble strips on noncontrolled-access highways include periodic gaps of 3.7 m (12 ft) in length, and that these gaps be placed at periodic intervals at a recommended spacing of 12.2 m (40 ft) or 18.3 m (60 ft).

Author(s):  
Erika B. Smith ◽  
John N. Ivan

With the encouragement of FHWA, many states are installing shoulder rumble strips to reduce the number of run-off-the-road crashes. In 1996, Connecticut began full-scale installation of shoulder rumble strips on limited-access highways (freeways). This paper describes research aimed at answering three questions about the effectiveness of this project: (a) Do rumble strips reduce single-vehicle, fixed-object crashes? The analysis indicates that installing shoulder rumble strips reduces these crashes by 33%. (b) Do certain roadway factors influence the rate of these crashes with regard to the rumble strip installation locations? In the sections where rumble strips were installed, run-off-the-road crashes were reduced by as much as 48.5% in interchange areas and as little as 12.8% on sections of roadways where the speed limit was less than 65 mph. (c) Is the potential adverse effect of crash migration (from locations with rumble strips to those without) occurring? The roadway factors analyzed and sections of longer routes in Connecticut both indicate increases in run-off-the-road crashes where rumble strips are not placed, even when exposure is controlled. These findings indicate that for rumble strips to be most effective along freeways, consideration should be made for continuous installation both to reduce crashes where they are installed and to avoid increases in crash occurrence where they are not.


2018 ◽  
Vol 36 (3) ◽  
pp. 330-340 ◽  
Author(s):  
Adalberto Di Benedetto ◽  
Claudio Galmarini ◽  
Jorge Tognetti

ABSTRACT Climbing Epipremnum aureum plants develop larger leaves than unsupported, hanging plants. This effect may be regarded, in part, as a thigmomorphogenic response, but gravimorphogenetic effect may also be involved, since polar auxin transport is known to be negatively affected in plants with horizontal or hanging stems, which may result in an altered hormone balance at the whole plant level. The present work was aimed at studying how exogenous auxins and cytokinins may influence growth of E. aureum rooted cuttings under different training systems. Rooted cuttings of E. aureum were cultivated either climbing on an upright wooden board or creeping on the glasshouse bench or hanging from a basket. All leaves of each plant were sprayed to run-off at sunset with four indole-3-acetic acid (IAA) doses 7 days after transplanting and one week later, with four benzylaminopurine (BAP) concentrations, rendering 16 hormone combination treatments. The application of IAA or BAP at 50 mg L-1 to creeping and hanging plants significantly promoted growth but, in climbing plants, a negative effect was generally observed. Changes in net assimilation and photosynthetic rates, together with modified allometric coefficients, accounted for these responses. The higher growth promotion by exogenous growth regulators observed in creeping or hanging plants compared to climbing plants, may be interpreted mostly as a gravimorphogenetic response.


2007 ◽  
Vol 87 (5) ◽  
pp. 1069-1074 ◽  
Author(s):  
David J. Blockley ◽  
Victoria J. Cole ◽  
Julie People ◽  
M. Gabriela Palomo

The distribution and abundance of intertidal organisms can be affected by short-term events, such as rain. We compared the effects of rain on intertidal mobile invertebrates in four common microhabitats with differing amounts of shelter (namely beds of oysters, coralline turf, bare patches and crevices) on sea walls in Sydney Harbour. There was an effect of rain on some, but not all taxa, although this was not consistent between locations or times. Effects of rain were observed for some species of gastropods and crustaceans, but not for polychaetes. Manipulative experiments using artificial rain indicated that rain, without the presence of run-off and independent of potential temporal confounding from differences in weather conditions, has a negative effect on abundances of amphipods in coralline turf. Pulse responses by mobile organisms to short-term rain events should be considered when designing experiments looking at temporal variability and processes responsible for observed patterns of distribution of marine organisms.


2016 ◽  
Vol 43 (2) ◽  
pp. 132-138 ◽  
Author(s):  
Mohamed Shawky ◽  
Hany M. Hassan ◽  
Atef M. Garib ◽  
Hussain A. Al-Harthei

Recently, the severity of injuries resulting from traffic crashes has been extensively investigated in numerous studies. However, the number of studies that addressed the severity of the run-off-road (ROR) crashes is relatively low. In the Emirate of Abu Dhabi (AD), approximately 22% of the total serious crashes and fatalities that occurred from 2007 to 2013 were ROR crashes. Despite these facts and the uniqueness of the composition of licensed drivers in AD (approximately 87% of them are non-Emiratis), the factors affecting the occurrence and severity of ROR crashes in AD have not been explicitly addressed in any prior studies. Therefore, this study aims to investigate the characteristics of at-fault drivers involved in ROR crashes in AD, the nature and main causes of those crashes. In this regard, conditional distribution and two-way contingency tables were developed. In addition, this study aims to identify and quantify the factors affecting the severity of ROR crashes such as driver, road, vehicle and environment factors. To achieve this goal, ordered probit model approach was employed. Crash data for a total of 3819 ROR crashes that occurred in AD were employed in the analysis. The results indicated that driver factors (carelessness, speeding, and nationality), vehicle characteristics (vehicle type), and road and environment factors (road type, crash location and road surface condition) were the significant factors influencing the severity of ROR crashes in AD. Countermeasures to improve traffic safety and reduce numbers and severity of ROR crashes in AD were discussed.


2012 ◽  
Vol 50 (2) ◽  
Author(s):  
Uttara Roy ◽  
Sunanda Dissanayake

This study examines the trends, characteristics, as well as contributory causes associated with run-off-road (ROR) and non-run-off-road (NROR) crashes. Likelihood ratios of these causes for ROR crashes with respect to NROR crashes are assessed using the Bayesian Statistical Approach. Nighttime, weekends, adverse weather, rural area, gravel and curved roads, higher speed limits, wet and icy road surface, and utility vehicles are found to be the common characteristics of ROR crashes. Fell asleep, ill or medical condition, driving under the influence, too fast for conditions, tires and wheels, strong winds, freezing rain, shoulders, ruts, holes, and bumps are found to have the greatest likelihood ratios and as such have a greater role in contributing to ROR crashes than NROR crashes.


2021 ◽  
Author(s):  
Xu Lin

Fatigue-related crashes are believed to be more common on rural highways than on urban roads and on two-lane roads rather than on other rural road types. Thus an understanding of how design factors affect fatigue-related crashes on rural to-lane roads is vital. The problem is that fatigue is rarely reported as a cause of crashes, since is is rarely suspected by the police as a possible cause and since potential liability may motive the drivers not to reveal the real causes of the crash. Thus, getting a handle on these crashes thorough modeling is a formidable challenge. Fortunately, there is research to suggest that single-vehicle run-off-road crashes, particularly those during periods of low circadian rhythm, can be used as a reasonable surrogate in modeling fatigue--related crashes. The paper is based on research to examine how fatigue-related crashes rural on two-lane roads, as represented by single vehicle crashes, are affected by various engineering design factors. This study's goal is to explore the effects of fatigue on driving on rural two-lane roads in North America, and to consider how we can work towards mitigating the effects of fatigue on traffic safety. For this investigation, generalized linear and logistic regression modelling were used on US Highway Safety Information System (HSIS) data from Ohio. Models were developed separately and combined for periods of high and low circadian rhythm and for single-vehicle run-off-road and other crashes. The results show, for example, the after controlling for traffic volumes, increases in speed limit, average curvature and average gradient and decreases in surface width and average shoulder width were found to be associated with increased fatigue related crashes. Important differences were found in the effects of factors for period of low and high circadian rhythm.


2016 ◽  
Vol 6 (2) ◽  
pp. 351-361
Author(s):  
C. Stefan ◽  
R. Stütz ◽  
E. Tomasch ◽  
P. Luttenberger ◽  
C. Klein
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