Road Crossings Research Articles

The ‘Shoots Barrage’: An Indicative Energy Technology Assessment of a Tidal Power Scheme

Several tidal power schemes have been proposed for the River Severn Estuary between the South West of England and Wales. An indicative technology assessment has been undertaken in order to evaluate the so-called ‘Shoots Barrage’ over its foreseen lifespan of 120 years in terms of its cradle-to-site, operation and maintenance requirements. It would be located just upriver of the Severn road crossings in the United Kingdom (UK), involve an estimated cost of £3.2 bn to construct, and could potentially generate around 2.7 TWh per year (or a little under 1% of UK electricity demand). This scheme is favoured by environmental groups, because to its more benign environmental impacts compared with the much larger, Cardiff-Weston scheme. The present analysis suggests that the proposed Shoots Barrage would yield relatively attractive ‘figures of merit’ in terms of its net energy and carbon emissions, although its financial performance is poorer than alternative power generators.

A closed form solution method for rapid calculation of guided wave dispersion curves for pipes

Guided wave inspection is a fast growing technology for screening pipelines for corrosion. The technique is capable of inspecting tens of metres from a single test location and examining otherwise inaccessible regions of pipeline such as cased road crossings. However, enhancements to the technique are needed if inspections are to be transformed from a screening procedure to a more quantitative assessment of the condition of the pipeline. A rapid calculation procedure to determine the dispersion curves for guided wave modes is important if enhancements are to be automatically incorporated into the technique. Commercial code for dispersion curve calculation is available but it is proprietary and typically uses an iterative procedure to calculate curves which can be unreliable and slow. Other methods for calculating dispersion curves have been published including semi-analytical finite element solutions but these require extensive programming. In this paper, a closed form solution based on known trigonometric behaviour in the circumferential and axial directions and a standard polynomial solution through the thickness is presented. The method allows rapid computation of dispersion curves for typical guided wave inspection scenarios with minimal programming required. In addition, a tracing algorithm is also presented which allows the computed points to be joined to form curves and therefore fully identify the dispersive behaviour of each wave mode. The new method has been successfully verified against the well-established software, Disperse®, for a range of pipe sizes, materials and frequencies typical to guided wave inspection.

Simulation and empirical analysis of novel sibship-based genetic determination of fish passage

We develop and test a new analytic approach, termed “sib-split”, to detect fish passage through road crossings. This new approach is based on the genetic analysis of full-siblings on opposite sides of potential barriers. We used simulations and data from two empirical case studies involving brook trout (Salvelinus fontinalis) movement with respect to barriers that varied in strength of effect on fish passage. Simulations revealed that both sib-split and the population assignment-based method (STRUCTURE) were highly accurate (mean accuracy > 99%) under easy-to-detect conditions (moderate to strong genetic differentiation and no movement). However, under difficult-to-detect simulated conditions (no genetic differentiation, 10% movement each generation), sib-split had higher accuracy (mean accuracy = 98%) than STRUCTURE (mean accuracy = 84%). Sib-split also outperformed STRUCTURE (mean accuracy 98% versus 89%) under a more difficult-to-detect simulated management scenario (simulated construction of a new complete barrier to movement). Sib-split provided more reliable and easily interpretable movement detection in both easy- and difficult-to-detect empirical case studies. With the empirical case studies, sensitivity to the prior on migration rate precluded use of STRUCTURE by itself, but a two-step approach where sib-split results were used to provide an informed migration prior for STRUCTURE provided additional information for both case studies.

Avoidance of high traffic levels results in lower risk of wild boar-vehicle accidents

Traffic accidents between cars and wildlife cause loss of lives, suffering and economic loss. Many studies have quantified the characteristics of accident sites, but factors affecting wildlife behaviour near roads and traffic are less explored. Hence, the mechanisms affecting animal movement and collision risks are poorly understood. Previous work suggests that roads and traffic may alter the behaviour of many animals, with temporal and spatial effects on daily movements, migration patterns and land cover selection. Here we analyze data from GPS-collared female wild boar (Sus scrofa) in Sweden to study factors affecting road crossings and traffic accidents involving wild boar. Our results show that wild boar cross roads in habitats mainly used for foraging. Avoidance of traffic results in few accidents at high traffic levels, causing most accidents to occur at intermediate traffic levels. A conclusion from this study is that wild boar appears to be able to make behavioural adjustments that reduce the risk of close vehicle encounters. Applications of these results for mitigating accidents between wild boar and vehicles involve changes in behavioural patterns of drivers and changes in farming practices close to accident prone roads.

Rockfall hazard assessment along a road on the Peloritani Mountains (northeastern Sicily, Italy)

Abstract. A hazard assessment has been performed on rock slopes impending over a segment of the Taorminese Road, which connects two popular tourist destinations in northeastern Sicily: the urban centers of Taormina and Castelmola. The road crosses steep rock slopes with a complex geological and tectonic history. The section of the road close to Castelmola is often affected by rockfall phenomena, causing injury to people and serious damage to buildings and traffic. The study analyzes the geostructural setting of the unstable rock masses, by evaluating their mechanical properties and the kinematics of potential failures. Rockfall simulations confirm that falling rocks would involve the Taorminese Road with different kinetic energy rates and prove useful for suggesting the most suitable mitigation technologies for future remedial works. The modified Rockfall Hazard Rating System has been applied to highlight the different levels of hazard along the road. The compiled hazard map shows that portions of the slopes need urgent remedial works, especially because Taorminese is the only access road to Castelmola and its interruption would lead to the isolation of the village.

Characteristics of the Road and Surrounding Environment in Metropolitan Shopping Strips: Association with the Frequency and Severity of Single-Vehicle Crashes

Objectives: Modeling crash risk in urban areas is more complicated than in rural areas due to the complexity of the environment and the difficulty obtaining data to fully characterize the road and surrounding environment. Knowledge of factors that impact crash risk and severity in urban areas can be used for countermeasure development and the design of risk assessment tools for practitioners. This research aimed to identify the characteristics of the road and roadside, surrounding environment, and sociodemographic factors associated with single-vehicle crash (SVC) frequency and severity in complex urban environments, namely, strip shopping center road segments.Methods: A comprehensive evidence-based list of data required for measuring the influence of the road, roadside, and other factors on crash risk was developed. The data included a broader range of factors than those traditionally considered in accident prediction models. One hundred and forty-two strip shopping segments located on arterial roads in metropolitan Melbourne, Australia, were identified. Police-reported casualty data were used to determine how many SVC occurred on the segments between 2005 and 2009. Data describing segment characteristics were collected from a diverse range of sources; for example, administrative government databases (traffic volume, speed limit, pavement condition, sociodemographic data, liquor licensing), detailed maps, on-line image sources, and digital images of arterial roads collected for the Victorian state road authority. Regression models for count data were used to identify factors associated with SVC frequency. Logistic regression was used to determine factors associated with serious and fatal outcomes.Results: One hundred and seventy SVC occurred on the 142 selected road segments during the 5-year study period. A range of factors including traffic exposure, road cross section (curves, presence of median), road type, requirement for sharing the road with other vehicle types (trams and bicycles), roadside poles, and local amenities were associated with SVC frequency. A different set of risk factors was associated with the odds of a crash leading to a severe outcome: segment length, road cross section (curves, carriageway width), pavement condition, local amenities and vehicle, and driver factors. The presence of curves was the only factor associated with both SVC frequency and severity.Conclusions: A range of risk factors were associated with SVC frequency and severity in complex urban areas (metropolitan shopping strips), including traditionally studied characteristics such as traffic density and road design but also less commonly studied characteristics such as local amenities. Future behavioral research is needed to further investigate how and why these factors change the risk and severity of crashes before effective countermeasures can be developed.

Effects of Road Crossings on Habitat Connectivity for Stream‐Resident Fish

AbstractRoad crossings can act as barriers to the movement of stream fishes, resulting in habitat fragmentation, reduced population resilience to environmental disturbance and higher risks of extinction. Strategic barrier removal has the potential to improve connectivity in stream networks, but managers lack a consistent framework for determining which projects will most benefit target species. The objective of this study is to develop a method for identifying and prioritizing action on road crossings in order to restore stream network connectivity. We demonstrate the method using a case study from the Pine‐Popple watershed in Wisconsin. First, we propose a new metric for quantifying stream connectivity status for stream‐resident fish. The metric quantifies the individual and cumulative effects of barriers on reach and watershed level connectivity, while accounting for natural barriers, distance‐based dispersal limitations and variation in habitat type and quality. We conducted a comprehensive field survey of road crossings in the watershed to identify barriers and estimate replacement costs. Of the 190 surveyed road crossings, 74% were determined to be barriers to the movement of at least one species or life stage of fish, primarily due to high water velocity, low water depth or outlet drops. The results of the barrier removal prioritization show that initial projects targeted for mitigation create much greater improvements in connectivity per unit cost than later projects. Benefit–cost curves from this type of analysis can be used to evaluate potential projects within and among watersheds and minimize overall expenditures for specified restoration targets. Copyright © 2014 John Wiley & Sons, Ltd.

Blanding's Turtles (Emydoidea blandingii) Avoid Crossing Unpaved and Paved Roads

Abstract Fragmentation of natural landscapes by linear anthropogenic features, such as roads, has several negative consequences, including decreasing connectivity between habitats, inhibiting animal movements, and isolating populations. Roads limit animal movements through behavioral avoidance and mortality during crossing attempts. We investigated the impact of a road network on the movement patterns of Blanding's Turtles (Emydoidea blandingii) in Quebec, Canada. We tested the hypothesis that roads act as a barrier to movements. We monitored 52 Blanding's Turtles (22 females, 24 males, and 6 juveniles) via radiotelemetry during their active season from May to August 2010. Road avoidance was quantified for each individual by comparing the number of inferred road crossings with the number of expected road crossings predicted by 1,000 movement path randomizations. Overall, Blanding's Turtles significantly avoided crossing roads. Roads were a significant barrier to movement for 3–6 of the 52 turtles, and an ...

Keep the children walking: active school travel in Tirana, Albania

This paper examines how characteristics of the physical and socio-economic environment influence children’s school travel mode in Tirana, the capital of Albania. A survey of students aged 11 to 13, revealed that an overwhelming majority walk to school, while bicycling and bus use are minimal. Students who walk to school often do so as part of a larger group of schoolmates, attend schools that are located relatively near their house, are faced with relatively few major road crossings during their journey, and belong to families that are less likely to own a car. Children who are driven to school (only 13.5% of our sample) usually have higher-income families and live farther from the school. Although Tirana’s high residential density has some environmental drawbacks, we deem it positive in that its result is that most students live very close to their schools and in close proximity to classmates walking to school. The fine grain pattern of the urban public school network contributes to the short distances between schools and homes. We provide a number of recommendations for the promotion of walking in home-school trips, as well as for the future physical development of the city and the school network.

Difficulties and prospects of fishways in China: An overview of the construction status and operation practice since 2000

Fish passage facilities are an effective means for mitigating the effect of barriers (e.g., dams, weirs, and road crossings) on migrating fishes. Fishways in China were first recorded in 1958. The efficiency of fishways is one of the evaluation indicators of a river ecosystem's health. This paper summarises and analyses China's construction of fishways since 2000. Three typical cases (Changzhou water control project, Laolongkou water control project and Cao’e river gate project) are presented to illustrate the current situation of fishways in China. A discussion is also provided regarding ideological guidance, theoretical systems, technical means (monitoring), research content, legal systems and other aspects to elaborate the deficiencies and challenges of China's fishways. Thus, a number of prospects, such as proposing the design criterion of fish passages, performing basin ecological protection planning, and implementing adaptive management are urgent and necessary for further development of fishways in China.

Pedestrian gestures increase driver yielding at uncontrolled mid-block road crossings

To protect pedestrians, many countries give them priority at uncontrolled mid-block crosswalks or pedestrian crossings. However, the actual driver yielding rate is not always satisfactory (only 3.5% in this study). To increase the yielding rate, this study proposed eleven pedestrian gestures to inform drivers of their intent to cross. The gestures were evaluated based on the process of human interaction with environment. Four gestures were selected as candidates to test in field experiments based on scores for visibility, clarity, familiarity and courtesy (see illustration in Fig. 2): (1) right elbow bent with hands erect and palm facing left (R-bent-erect), (2) left elbow bent with hands level and palm facing left (L-bent-level), (3) left arm extended straight to left side with palm erect facing left (L-straight-erect), and (4) a ‘T’ gesture for “Time-out”. In the experiment, confederate pedestrians waiting at the roadside displayed the gestures (baseline: no gesture) to 420 vehicles at 5 sites in Beijing, China. When pedestrians used the L-bent-level gesture, the vehicle yielding rate more than tripled of that in the baseline condition. The L-bent-level gesture also resulted in a significant decrease in driving with unchanged speed (63.5–38.8%) and had no significant side effects in terms of drivers’ horn use or lane changing. The effects of such gestures in other contexts such as when pedestrians are in the crosswalk and when they are interacting with turning vehicles are discussed, together with the applications in training vulnerable pedestrian groups (children or elderly) and facilitating pedestrian detection by drivers.

Explaining Pedestrian Safety Experience at Urban and Suburban Street Crossings Considering Observed Conflicts and Pedestrian Counts

This article presents an investigation of pedestrian conflicts and crash count models to learn which exposure measures and roadway or roadside characteristics significantly influence pedestrian safety at road crossings. Negative binomial and ordered proportional odds technique were used to estimate pedestrian conflict count and severity models. Pedestrian counts and conflicts data were collected at 100 locations throughout Connecticut. Pedestrian crash data were collected from the Connecticut Crash Data Repository. The results show that minor and serious conflicts are marginally significant in predicting total pedestrian crashes together with crossing distance and building setback. This suggests that these conflicts may be a good surrogate for crashes in analyzing pedestrian safety. Greater crossing distance and small building setbacks are found to be associated with larger numbers of pedestrian–vehicle crashes. This latter effect is not expected, because we expect vehicle speeds to be lower in areas where the building setback is small. This factor may account for the greater pedestrian activity and more complex interactions in such areas. Further research aimed at identifying a minimum length of time for accurate estimation of pedestrian volume and conflicts to relate to crashes is the subject of continuing investigation by the authors.

Targeting mitigation efforts: The role of speed limit and road edge clearance for deer–vehicle collisions

ABSTRACTDeer–vehicle collisions (DVCs) have major social, economic, and animal welfare costs. Modeling of accident risk relative to environmental characteristics could enable managers to plan the layout of new roads or determine optimal location of mitigation measures to reduce the number of accidents on existing roads. We analyzed position data providing road crossings from 67 global positioning system (GPS)‐marked red deer (Cervus elaphus) and location data of 271 car killed deer within the home ranges of the GPS‐marked red deer. We modeled collision risk as a function of speed limit, season, road characteristics, and habitat features. For a subset of the data, we tested if vegetation clearance along a highway reduced the collision frequency of red deer. The relative risk for DVCs increased with speed limit. We found a higher risk for DVCs during winter compared to the other seasons. Forest cover, distance to pasture, and terrain ruggedness substantially affected risk of DVCs. Road edge clearance reduced the frequency of DVCs, but the effect appeared in the winter season only with a decrease of 53%. Our study highlights that speed limit reduction and road edge clearance are both powerful mitigation tools to reduce the number of DVCs. © 2014 The Wildlife Society.

Automatic filtering of vehicles from mobile LiDAR datasets

This manuscript presents a new filter to automatically remove vehicles from point clouds of roads captured by a mobile LiDAR system. The algorithm works in two main steps. The first one consists of the normalization and segmentation of the point cloud in order to homogenize the density of points in all areas corrected as function of vehicle speed. The second step is based on detecting changes of slope on the transversal profiles of the roads digitalized by LiDAR, inside the contours defined by the traffic lines that limit the road space. Profiles are produced by the rotation of the LiDAR mirror. Once detected those points of the LiDAR echoes that correspond to the vehicle they are automatically removed. Finally, the point cloud is regenerated using commercial software that creates new points based on parametric surfaces, fitting the points of the neighborhood of each hole produced by the elimination of vehicle points.The algorithms developed are tested by checking the successful of the vehicle detection and the geometric comparison of longitudinal profiles and cross sections, before and after the filter application. Results show as all the vehicles were successfully detected and corresponding echoes cleaned. Road profile and cross sections reveal that the generated geometries are in agreement with the real geometries of the road.

Understanding the mechanisms behind road effects: linking occurrence with road mortality in owls

AbstractSeveral studies suggest that species' mortality rates are positively related with local population abundances. Because owls have shown both high road mortality rates and road avoidance behaviours, we hypothesize that road‐kill likelihood is not always directly linked to their occurrence. In this study, we examined the relationship between the likelihood of species occurrence in the vicinity of major roads and the road‐kill risk for barn owls Tyto alba, tawny owls Strix aluco and little owls Athene noctua. Specifically, we address: (1) the role of road‐related features on spatial patterns of species' occurrence and road kills; (2) the composition of road kills and their distribution throughout the year; (3) the relationship between species' occurrence likelihood and mortality risk. Our findings show that changes in movement patterns is probably the main behavioural mechanism that threatens owls in roaded landscapes. The high mortality risk of barn owls in autumn and winter seasons, after the peak of dispersal period, provides support for the hypotheses of expanding movements because of lack of food. However, mortality because of high occurrence likelihood seems to also explain tawny owls' response towards roads. The high occurrence likelihood of little owls combined with low mortality rate also suggests avoidance of road crossings. Although, it is clear that within species there is variation according to age‐ and territory‐holding status, closely related species have different sensitivities to roads as a function of their varying food preferences. We believe that linking species distribution with mortality risk may be more effective in focus conservation efforts. Therefore, we suggest measures should be applied to reduce prey availability close to roads and in road verges. This is particularly important for barn owls, for which foraging in the vicinity of roads during the cold season is especially risky.

Parental safety concerns and active school commute: correlates across multiple domains in the home-to-school journey

BackgroundEmpirical evidence of the relationship between safety concerns and walking to school (WTS) is growing. However, current research offers limited understanding of the multiple domains of parental safety concerns and the specific mechanisms through which parents articulate safety concerns about WTS. A more detailed understanding is needed to inform environmental and policy interventions. This study examined the relationships between both traffic safety and personal safety concerns and WTS in the U.S.MethodsThis cross-sectional analysis examined data from the Texas Childhood Obesity Prevention Policy Evaluation (T-COPPE) project, an evaluation of state-wide obesity prevention policy interventions. All study data were from the survey (n = 830) of parents with 4th grade students attending 81 elementary schools across Texas, and living within two miles from their children's schools. Traffic safety and personal safety concerns were captured for the home neighborhood, en-route to school, and school environments. Binary logistic regression analysis was used to assess the odds of WTS controlling for significant covariates.ResultsOverall, 18% of parents reported that their child walked to school on most days of the week. For traffic safety, students were more likely to walk to school if their parent reported favorable perceptions about the following items in the home neighborhood environment: higher sidewalk availability, well maintained sidewalks and safe road crossings. For the route to school, the odds of WTS were higher for those who reported "no problem" with each one of the following: traffic speed, amount of traffic, sidewalks/pathways, intersection/crossing safety, and crossing guards, when compared to those that reported "always a problem". For personal safety in the en-route to school environment, the odds of WTS were lower when parents reported concerns about: stray or dangerous animals and availability of others with whom to walk.ConclusionsFindings offered insights into the specific issues that drive safety concerns for elementary school children’s WTS behaviors. The observed associations between more favorable perceptions of safety and WTS provide further justification for practical intervention strategies to reduce WTS barriers that can potentially bring long-term physical activity and health benefits to school-aged children.

Connectivity influences on nutrient and sediment migration in the Wartburg catchment, KwaZulu-Natal Province, South Africa

Non-point-source (NPS) pollution of surface and groundwater by sediment and nutrient loads emanating from agricultural catchments is a prominent environmental issue, with major consequences on water supply and aquatic ecosystem quality. The concept of connectivity has proved invaluable in understanding migration of NPS pollutants in catchments. Observations of sediments or suspended solids (SS), nitrate (NO3) and phosphorous (P) fluxes alongside stable water isotope sampling were made on a nested basis at field and catchment (41km2) scales for a series of events in the Wartburg catchment, South Africa. The nested catchment scale sampling was focused on control features in the stream network, including road crossings, farm dams and wetland zones. The analyzed stable water (δ18O and δ2H) isotopes results were used to interpret the connectivity of the contributing land forms and the stream network. The results reveal the dominant influences of farm dams and wetlands in limiting the downstream migration of sediment and nutrients for all but the most intense events. Certain events resulted in mixing in the dams and larger resultant outflow than inflow loads. These occurrences appear to be as a result of combinations of reservoir status, catchment antecedent conditions and rainfall depth and intensity. The nutrients loads between Bridge 1 and Bridge 2 stations reflect the bedrock control, where contributions from sugar cane hillslopes between these stations are not retained, even in the short wetland upstream of Bridge 2. Isotope analyses reveal that the headwaters, comprising 70% of the catchment area, contribute as little as 29% of the total catchment discharge, due to impoundments in this area. However, this contribution varies significantly for different events, reaching a maximum of 78% of the catchment discharge. It can therefore be concluded that nutrients and sediment migration in the Wartburg catchment is greatly influenced by connectivity. The δ18O and δ2H water isotopes can be used to assess the contributions of different sources of water which impact the transport of nutrients and sediments in catchments.

The Effect of Road Crossing on River Morphology and Riverine Aquatic Life: A Case Study in Kunur River Basin, West Bengal

Road crossings play important role in land transport system, but improper designed stream crossing may alter the form and function of stream geomorphology, floodplain ecosystem, habitat and movement of aquatic organisms. The objective of this paper is to explain the local level impact of a road crossing on channel morphology and aquatic lives of the Kunur River, based on geomorphic survey and stream classification. This study shows a comparison between upstream and downstream reaches of Kunur River where the State Highway-14 crossed the river over a bridge. There are changing fluvio-geomorphic indicators like mean and maximum bankfull channel depth, cross-section area, flow velocity, entrenchment ratio, channel bed gradient, water level and depth, braided index (BI), pool-riffle sequence, area and shape of bars, and others taken into consideration. Results are temporally increases of BI and expansions of bars. In the downstream, river channel is deeply incised by massive bed degradation and highly entrenched with high flow velocity and steep channel bed gradient, low entrenchment ratio (<2.2), low width-depth ratio (11.26) and increasing inter pool-riffle distance. Present study reveals that bank failure is a common phenomenon here with deep scours and making unsuitable environment for fish habitat. Alternatively, it has appeared to be greater deposition of fine sediment in the upstream reaches with high braiding index, area of bars. High entrenchment ratio (>2.2) and width-depth ratio (>35) also indicates well developed floodplain ecosystem here.Key Words: Anthropogenic feature; channel morphology; bed degradation; bank failure; fine sediment

Analysis of Domestic Media Reported Burst Events on Water Distribution System in 2012

By means of the Internet platform for rapid and timely, the relevant data of domestic media in 2012 reported burst events were collected and collated. The statistics showed that burst mainly occurred in the southern coastal cities; winter was the main season for burst, especially in January, February and December; in July burst also was frequent; 5:00-17:00 was a dangerous phase during a whole day; the trunk road intersection or crossings and the construction site were more likely to become the incident locations. Generally recognizing that improper construction and aging were the main reasons for burst. The diameter of burst was concentrated in DN300-DN600, DN800 and DN1000-DN1200, especially in DN600. Pipes of cast iron pipes and cement pipes, and pipes pipeline in 20-30 years old was more likely to burst.

De la arquitectura religiosa utópica a la evangelización en los no-lugares

Buena parte de la arquitectura religiosa contemporánea está constituida por iglesias parroquiales. El término parroquia equivale etimológicamente a vecindad, aunque tiene la connotación bíblica de comunidad extranjera, emigrante o peregrina. Esta dimensión escatológica de orientación hacia Cristo y la Parusía es la utopía cristiana. En contraste, la arquitectura utópica de la sobremodernidad, en tanto que no-lugar, resulta a priori no-religiosa. Sin embargo, hoy podemos analizar propuestas que acompañan la fe de los usuarios en el tránsito y quehacer cotidiano, en diálogo con las tradicionales cruces de término, humilladeros y ermitas.