Small Road Research Articles

Equivalent gap function-based reformulation and solution algorithm for the dynamic user equilibrium problem

A variety of analytical and simulation-based models and algorithms have been developed for the dynamic user equilibrium (DUE) traffic assignment problem. This paper aims to develop a theoretically sound simulation-based DUE model and its solution algorithm, with particular emphasis on obtaining solutions that satisfy the DUE conditions. The DUE problem is reformulated, via a gap function, as a nonlinear minimization problem (NMP). The NMP is then solved by a column generation-based optimization procedure which embeds (i) a simulation-based dynamic network loading model to capture traffic dynamics and determine experienced path travel costs for a given path flow pattern and (ii) a path-swapping descent direction method to solve the restricted NMP defined by a subset of feasible paths. The descent direction method circumvents the need to compute the gradient of the objective function in finding search directions, or to determine suitable step sizes, which is especially valuable for large-scale simulation-based DUE applications. Computational results for both small and large real road networks confirm that the proposed formulation and solution algorithm are effective in obtaining near-optimal solutions to the DUE problem.

A Road Survey of Amphibians and Reptiles in a Bottomland Hardwood Forest

The impact of roads on amphibian and reptile numbers at Texas Parks and Wildlife Department's Old Sabine Bottom Wildlife Management Area (OSBWMA), a bottomland hardwood forest was studied from 1 June 2003 to 1 June 2004 by vehic- ular and pedestrian surveys. One weekly survey was conducted in the morning and the other in late afternoon. Vehicular surveys were conducted by driving 16.1 km/hr over the roads (9.5 km) through the bottomland twice per week. Pedestrian surveys were conducted on 6 sections of those roads (1.3, 1.3, 1.3, 1.1, 0.3, and 0.3 km), three on the larger main gravel road, and three sections on smaller dirt tributaries, twice weekly. One section of the main road (1.3 km) was located near three operat- ing oil rigs. The other 5 sections of the survey route traversed forested regions of the management area. The 3 sections located along the main gravel road were subject to regular vehicular traffi c by the public and OSBWMA staff. The three sections located along the dirt trail tributaries had primarily foot travel with much less and slower ve- hicular traffi c. GPS coordinate, date, and condition (alive or dead) of the specimens were recorded. In the summer, 10.5% of the amphibians and reptiles were found dead on the road (DOR). The number of DORs in the fall was 47.1%, and 64.3% in the spring. For amphibians, 28.1% were DOR (summer), 20% in the fall, and 83.3% in the spring. In the winter months, no specimens were observed on the roads. Road traffi c in this bottomland impacts reptiles extensively in the fall and amphibians in the summer, whereas both reptiles and amphibians are affected by road traffi c in the spring. Smaller roads and the section of road with oil rigs had lower mortality rates, while areas with adjacent borrow pits had higher mortality rates.

Response of carnivores to existing highway culverts and underpasses: implications for road planning and mitigation

Roads with high traffic volumes are a source of animal mortality, can disrupt normal animal movements and dispersal, and may represent a potentially serious threat to wildlife population stability and viability. Retrofitting existing structures built for other purposes (e.g., drainage culverts or small below-grade access roads) to facilitate wildlife crossing by animals and to reduce mortality may be expensive if modifications to the existing structures themselves were involved. However, the environmental context surrounding these structures may influence the willingness of animals to cross, and management of some of these attributes may enhance the attractiveness of these structures. Culverts and underpasses are two common structures along roads in Portugal. We quantified the response of small and medium-sized carnivores to the presence of both types of existing passages by determining: (1) frequency of use; (2) whether use differed by type of passage, and if so; (3) by examining if associated environmental attributes might explain the differences observed. We surveyed 57 different passages along 252 km of highway with a total sampling effort of 2,330 passage trap-days. The mean passage rate for carnivores combined was 0.7 complete passages per crossing structure per day. Crossings by weasel, polecat, otter, and wildcat were infrequent or absent. Red fox, badger, genet and Egyptian mongoose used the crossing structures regularly and without obvious preference; stone marten preferred underpasses. Regression analyses showed the frequency of use by carnivores varied with structural, landscape, road-related features, and human disturbance with 17 of 26 (65%) attributes being significant. Larger passages with vegetation close to the passage entrances, favorable habitat in the surrounding area, and low disturbance by humans were important key features to regular use by the guild of species studied. Mitigation planning in areas with ecological significance for carnivores will be beneficial. Structural attributes and human disturbances are more difficult or expensive to change, even though related significantly to crossing use. Management of vegetation at passage entrances and restricting human use near passages in carnivore suitable areas may substantially improve crossing attractiveness for the guild of carnivore species.

Motion Description Language-Based Topological Maps for Robot Navigation

Robot navigation over large areas inevitably has to rely on maps of the environment. The standard manner in which such maps are defined is through geometry, e.g. through traversability grid maps or through a division of the environment into free-space and obstacle-space. In this paper, we combine certain aspects of the geometric maps, through the notion of distinctive places, with a topological description of how these places are related. What is novel is the idea that the adjacency relation is defined by the existence of a control law that drives the robot between topologically connected places. Moreover, these maps can be automatically constructed based on the premise that the nodes correspond to places associated with a hightened control activity. 1. Introduction. The production of maps for navigation purposes only becomes meaningful if the maps are somehow coupled to their expected use. For example, a pedestrian map may contain many small roads, while an automotive map covering the same area only contains roads big enough for cars to drive on. Similarly, air- planes employ a completely different set of maps than land-based vehicles. What this somewhat informal discussion immediately tells us is that when maps are to be produced for robotics applications, they only become useful when they respect the constraints (may they be dynamic or geometric) imposed by the actual vehicle. This issue is highlighted clearly when constructing configuration spaces for mobile robots that take the spatial dimensions of the robots into account (12, 13). In this paper we make this observation concrete by explictly taking the capabilities of the robot into account through a collection of predetermined control modes (or behaviors). This navigation system structure, i.e. decomposing a task into building blocks, has proven to be useful in that it allows the designer to produce controllers that are dedicated to performing specialized tasks, such as avoiding obstacles, clearing steep gradients, approaching landmarks, and so on. (See for example (2, 7).) Rather than constructing a single controller, the high-level mission is executed by a supervisor that determines what mode of operation to use in a particular situation. The selection of a set of modes has implications for what the robot can actually do, which we intend to make explicit in this paper. As the mission scenarios for mobile robots become more elaborate, the trade- off between complexity and expressiveness of the map becomes an issue that must be taken into account (13, 18). In other words, a highly detailed map may not be particularly useful in that planning over this map might take too long as compared to

McMansions: The Extent and Regulation of Super-sized Houses

In response to the increase in oversized houses and plats, this paper reports the results of a survey of 103 US cities about the presence and extent of McMansion houses (infill and greenfield plats) and on their approaches to regulation. With a response rate of 57%, the results revealed that many cities have McMansions and some have adopted regulations (such as limiting building height, design review, and limiting floor area ratio) to control their development. As McMansions continue to spread, communities may need to consider more effective mechanisms to control for undesirable impacts—for infills on neighbours, and for greenfield plats on sprawl. On … a small road … four major construction projects are under way on individual lots. In each case, the existing, one-story home was sold and pulled down. A builder is now constructing a massive mansion some ten times larger than the pre-existing building on each lot … These large land-use changes in such a small area have significant effects on the town as a whole … tens of trees have been removed to make way for not only the massive buildings but also for the vast sprinkled lawns that surround them. Large decorative lawns and small clusters of shrubs is very different from the slightly overgrown woods … They also mean fertilizer, weed-killer, other chemical products … These changes of vegetation, and the increase in built area, alter both the flora and fauna of the area, especially when introduced on such a massive scale—not one mansion, but four and possibly five on the same small street! Second, when a new subdivision of million dollar plus homes is proposed, community members may have an opinion on the uncontrolled removal of smaller, more affordable homes for the young and/or the old members of our community. And finally, whatever your architectural tastes, no one can pretend that these homes are adding to the beauty of our town. But none of these objections would be meaningful if neighbourhood residents had been consulted, as we imagine they would have been if an entire new subdivision was proposed … By tearing down individual homes and replacing them, builders and realtors seem able to sidestep any conventional public approvals process. Only those of us who live nearby are aware that our neighbourhood is changing radically. (Letter to the editor, Carlisle Mosquito, 8 June 2002, John and Jacqueline Zeisel)

모포마 분포를 적용한 분단위 강우강도-지속시간-재현기간 관계의 유도

본 연구에서는 도로나 도시유역에서와 같은 소유역의 배수시스템에서 적정량의 설계 규모를 결정하기 위해 지속시간 10분 이하의 강우강도-지속시간-재현기간 관계를 유도할 수 있는 방안을 제시하고 검토하였다. 본 연구에서 제시하는 방법은 모포마 분포에 근거한 것이며, 그 적용성을 서울지점 자료에 대한 적용을 통해 확인하였다 본 연구의 결과를 정리하면 다음과 같다. (1) 1분단위 강우자료를 이용하여 빈도해석을 수행한 결과 기존 건설교통부 (2000)에 의해 제시된 강우강도식은 분단위로 외삽할 수 없음을 확인하였다. (2) 60분 집성자료를 모포마 분포에 적용하여 추정한 지속시간별 분단위 연최대치 강우계열은 관측된 분단위 연최대치 강우계열의 특성을 적절히 설명할 수 있는 것으로 파악되었다. (3) 60분 집성자료와 시단위 강우자료를 이용하여 모포마 분포에 적용한 IDF 관계의 차이는 미미한 것으로 나타났다. This study proposes and evaluates a methodology for deriving the rainfall intensity- duration-frequency relationship for durations less than 10 minutes used for designing drainage systems in small urban catchments and roads. The method proposed in this study is based on the Moupfouma distribution, which has been evaluated by applying it to the rainfall data at the meteorological Seoul station. Summarizing the results is as follows: (1) The frequency analysis results using minutely rainfall data was found not to be corresponded with the extrapolation of that by the Ministry of Construction and Transportation (2000). (2) The annual maxima minutely rainfall data derived by applying the Moupfouma distribution to the accumulated 60-minute data was found to well reproduce the characteristics of those of observed. (3) The rainfall intensity-duration-frequency relationship derived by applying the Moufouma distribution to the accumulated 50-minute data and hourly data was found insignificant.

Estimated Sand and Gravel Resources of the South Merrimack, Hillsborough County, New Hampshire, 7.5-Minute Quadrangle

A computer methodology is presented that allows natural aggregate producers, local governmental, and nongovernmental planners to define specific locations that may have sand and gravel deposits meeting user-specified minimum size, thickness, and geographic and geologic criteria, in areas where the surficial geology has been mapped. As an example, the surficial geologic map of the South Merrimack quadrangle was digitized and several digital geographic information system databases were downloaded from the internet and used to estimate the sand and gravel resources in the quadrangle. More than 41 percent of the South Merrimack quadrangle has been mapped as having sand and (or) gravel deposited by glacial meltwaters. These glaciofluvial areas are estimated to contain a total of 10 million m3 of material mapped as gravel, 60 million m3 of material mapped as mixed sand and gravel, and another 50 million m3 of material mapped as sand with minor silt. The mean thickness of these areas is about 1.95 meters. Twenty tracts were selected, each having individual areas of more than about 14 acres (5.67 hectares) of stratified glacial-meltwater sand and gravel deposits, at least 10-feet (3.0 m) of material above the watertable, and not sterilized by the proximity of buildings, roads, streams and other bodies of water, or railroads. The 20 tracts are estimated to contain between about 4 and 10 million short tons (st) of gravel and 20 and 30 million st of sand. The five most gravel-rich tracts contain about 71 to 82 percent of the gravel resources in all 20 tracts and about 54–56 percent of the sand. Using this methodology, and the above criteria, a group of four tracts, divided by narrow areas sterilized by a small stream and secondary roads, may have the highest potential in the quadrangle for sand and gravel resources.

Runoff and sediment yield from rural roads, trails and settlements in the upper Konto catchment, East Java, Indonesia

The potential importance of roads and settlements for the generation of storm runoff and sediment in tropical steeplands is increasingly recognised but rarely quantified. This paper presents runoff and sediment yield data for a cobbled and an unpaved road section, two large unbounded settlement plots, and several trails draining residential areas or terraced fields in a volcanic upland catchment in East Java. In addition, the sediment yield of major landslides associated with roads was quantified. The unpaved road section exhibited an average runoff coefficient of about 65% and yielded about 7 kg m − 2 yr − 1 of sediment. Both the runoff coefficient and the sediment yield for the cobbled road section (plus adjacent yards) were lower (38% and 1.9 kg m − 2 yr − 1 ). Sediment output from a 4160-m 2 hillside plot including a network of trails draining terraced fields (for which runoff and sediment outputs were shown to be negligible) was similar to that for the cobbled road (2–3 kg m − 2 yr − 1 depending on rainfall). However, a much higher value was obtained when the overall soil loss from the plot was expressed per square metre of trail surface area (ca. 42 kg m − 2 yr − 1 ) whereas the associated trail runoff coefficient was about 70%. The results obtained for several trails and large unbounded plots draining residential areas at two locations were less extreme (runoff coefficients of 24–43%; soil loss 1.3–3.5 kg m − 2 yr − 1 ). Landsliding occurred mainly at the end of the rainy season (March) and was estimated to have contributed ca. 2365 m 3 of sediment to the main road network during the 1988/89 wet season vs. ca. 905 m 3 in 1989/90 and only ca. 150 m 3 in 2000/01. It is concluded that, despite their relatively small areal extent (5% in the study area), rural roads, trails and settlements are significant producers of runoff and sediment at the catchment scale and should be included in watershed management programmes designed to reduce catchment sediment yields and reservoir siltation.

Optimal Routing Design for Shuttle Bus Service

A growing concern for public transit is its inability to encourage people to switch their mode of transportation from solo to shared driving. For example, most people arrive at rail stations via private cars; this creates traffic congestion and parking overloading in station areas. As a means of overcoming this problem, automated methods for designing circulated (shuttle, feeder) bus routes were developed. The problem input comprised an urban network with trip generation links and a single destination (main) node, average travel time between each link to the main node, and a constraint defining the maximal travel time along the route. The research components were threefold: ( a) a method for estimating potential passenger demand for a circulated (shuttle) bus route, ( b) an operations research model focusing on optimal route design, and ( c) a heuristic algorithm designed to account for road networks of all sizes. The optimal model and its heuristic alternative were compared in different scenarios on a small real-life road network. It was shown that the heuristic algorithm indeed provides good (optimal in the test case) results. The heuristic procedure was also implemented with medium and large networks, generated randomly, and found to provide good results within a reasonable running time.

Optimal Routing Design for Shuttle Bus Service

A growing concern for public transit is its inability to encourage people to switch their mode of transportation from solo to shared driving. For example, most people arrive at rail stations via private cars; this creates traffic congestion and parking overloading in station areas. As a means of overcoming this problem, automated methods for designing circulated (shuttle, feeder) bus routes were developed. The problem input comprised an urban network with trip generation links and a single destination (main) node, average travel time between each link to the main node, and a constraint defining the maximal travel time along the route. The research components were threefold: (a) a method for estimating potential passenger demand for a circulated (shuttle) bus route, (b) an operations research model focusing on optimal route design, and (c) a heuristic algorithm designed to account for road networks of all sizes. The optimal model and its heuristic alternative were compared in different scenarios on a small real-life road network. It was shown that the heuristic algorithm indeed provides good (optimal in the test case) results. The heuristic procedure was also implemented with medium and large networks, generated randomly, and found to provide good results within a reasonable running time.

「島根県中山間地域における人口減少のＧＩＳ分析」―集落ＧＩＳデータベースと農村計画への活用可能性―

This paper aims to make clear that the geographical tendency of population decrease in mountainous regions in Shimane Prefecture in recent years. Based on the data about small community population, road network and municipal offices, GIS (Geographic Information System) analysis indicates more peripheral parts of the regions show greater decrease of population and households as well as higher aged population rates. In order to adapt to these transition of regional population structure, it is necessary to build new sustainable management system in which GIS is considered to be a very promising planning tool.

Research on Steel Shell of a Road Bridge Made of Corrugated Plates during Backfilling

This paper presents the results and conclusions of the research conducted on a backfilled shell structure made of Super Cor SC-56B corrugated steel plates of a road bridge located in Gimån, Sweden. The conclusions drawn from the tests can be helpful mostly for the assessment of the behavior of this type of steel–soil bridge structure under the load of backfilling. In consideration of an even more frequent application of this type of structure for small and middle-sized road and rail bridges, conclusions from the conducted research can be generalized to the whole class of such structural solutions.

The inadequacy of the fish-bearing criterion for stream management

Dependence on the fish-bearing and non-fish-bearing designation in determining the regulation of stream management is questioned. The importance of intermittent, ephemeral, and very small first order channels as suppliers of invertebrates and detritus to permanently flowing, receiving streams that support juvenile salmonids warrant their protection during timber harvest. Small gravel bed roads serve many of the same functions as the small intermittent and ephemeral headwater channels. Therefore, many could be managed like small stream channels and eligible for exclusion from road decommissioning actions. Among the invertebrates inhabiting headwater streams, many have specific adaptations to low and seasonal flows. Given these considerations, it is clear that criteria other than the presence or absence of juvenile salmonids need to be considered in managing forested watersheds.

Tularemia after a dormouse bite in Switzerland

Reported here is a case of ulceroglandular tularemia acquired from a dormouse in a forest in northern Switzerland. To the best of our knowledge, this is the first description of this infection being transmitted from a dormouse to a human in this country, and it serves as a reminder that, although rare, the disease does occur naturally. While walking through a forest a 59-year-old physicist picked up a dormouse (Glis glis, Fig. 1) in order to remove it from a small road. The animal bit the man on the second digit of his left hand and didn’t release its bite until it was forcibly removed from the finger. The man presented to his family physician, where the wound was cleaned and a tetanus/diphtheria vaccine was administered. Initially the wound healed well, and after 2 days it was barely visible when the patient developed a flu-like syndrome with a temperature of 38◦C, headache, malaise and myalgia. While his temperature rose by 1◦C per day to a constant fever of 41◦C, the patient’s general condition remained good. A painful ulcer developed on his bitten finger, and later the entire hand swelled up and became discolored. Empiric therapy with amoxicillin/clavulanate lowered his fever to 37–38◦C after about 5 days, but the patient’s axillary lymph nodes enlarged slowly and became painful. As the finger’s appearance worsened, the patient was hospitalized 10 days after he was bitten. At admission, the patient’s finger and hand were swollen and discolored, and a dorsal ulcer was present at the site of the bite wound. His temperature was 37.8◦C, pulse 90/min and blood pressure 118/78 mmHg. Laboratory results showed a normal leukocyte count at 9300 /μl with a left shift of 54% and an elevated C-reactive protein level of

Small Retailers' Road to Success

The small retailer has a difficult time competing with large mass merchandisers, category killers, and retail chains. Price discounting is not an option, because the small retailer can never beat the price of large retail operations. Therefore, small retailers must look to other means of differentiation. This paper proposes a customer value concept that is based on the premise that customers are of varying value to a retail operation. Dividing a retailer's customer base into four buckets, marketing strategies are suggested for each group that will optimize a small retailer's marketing investment. The success of this type of marketing approach is based on an understanding of brand value, repeat purchase behavior of customers, and customer relationship management (CRM) technology.

Why Did the Snake Cross the Road? Effects of Roads on Movement and Location of Mates by Garter Snakes (Thamnophis sirtalis parietalis)

Shine, R., M. Lemaster, M. Wall, T. Langkilde and R. Mason 2004. Why Did the Snake Cross the Road? Effects of Roads on Movement and Location of Mates by Garter Snakes (Thamnophis sirtalis parietalis). Ecology and Society 9(1):9. https://doi.org/10.5751/ES-00624-090109

Estimation of Turning Movements at Intersections: Joint Trip Distribution and Traffic Assignment Program Combined with a Genetic Algorithm

The availability of turning movement data at intersections is essential in carrying out traffic simulations with software such as NETSIM. However, data collection is very time-consuming even for a small network. To estimate turning movements at intersections, a logit-based stochastic user equilibrium (SUE) model was integrated into a genetic algorithm. Three derivative models were developed: ( a) a doubly constrained estimator, ( b) a singly constrained estimator, and ( c) an origin-destination (O-D)-based estimator. In the first and second estimators, the SUE model was formulated as a joint trip distribution and traffic assignment (TD-TA) program, whereas in the third estimator, the SUE model was based on a standard O-D distribution program. These turning movement estimator models were examined by applying them to three road networks: a virtual road network with simulated data, a small road network in the field with data obtained by manual counting, and a road network with data measured with traffic detectors. Application of the models to the virtual road network proves that if prior information on the O-D distribution is available, the O-D-based estimator is most effective in estimating turning movements. Application of the models to real networks for which no prior information on the O-D flows is available shows that the doubly constrained TD-TA-based model is the most accurate and efficient. The turning movements on major links estimated with this model were in relatively good agreement with those actually measured. The correlation coefficient of link flow exceeded 0.90. However, the rationale of the range of unknown variables remains unresolved.

Roads as barriers to movement for hedgehogs

Summary1. Movements of hedgehogs,Erinaceus europaeusL., were analysed in relation to roads by recording their nocturnal foraging trajectories in urban areas adjacent to major road systems. Four male and four female hedgehogs at each of two sites were each tracked over five replicate trajectories of more than 3 h, using radio‐telemetry and direct observation.2. Frequency of road crossings and use of habitat were compared to simulated random trajectories. For each observed trajectory, 100 trajectories were simulated with the same distribution of speeds as observed, but with random direction.3. Observed trajectories had lower rates of crossing large but not small roads than simulated, indicating that hedgehogs treat large roads as barriers during nightly foraging activities. Most hedgehogs were never observed to cross roads, whereas almost all simulated trajectories did cross both large and small roads.4. Crossing behaviour differed by site, but not by sex.5. Roads and road verges had the lowest rank in a habitat preference analysis at both sites, while playing fields, gardens and urban areas were preferred habitats. These results are discussed in relation to the regional scale preference for urban areas, and the attraction to road verges while dispersing, shown by hedgehogs.

The influence of management history and habitat on plant species richness in a rural hemiboreal landscape, Sweden

We explored patterns of plant species richness at different spatialscales in 14 habitats in a Swedish rural landscape. Effects of physicalconditions, and relationships between species richness and management historyreaching back to the 17th century were examined, using old cadastralmaps andaerial photographs. The most species-rich habitats were dry open semi-naturalgrasslands, midfield islets and road verges. Alpha diversity (species richnesswithin sites) was highest in habitats on dry substrates (excluding bedrock withsparse pines) and beta diversity (species richness among sites) was highest inmoist to wet habitats. Alpha and beta components of species richness tended tobe inversely related among habitats with similar species richness. Managementhistory influenced diversity patterns. Areas managed as grasslands in the17th and 18th century harboured more species than areasoutside the villages. We also found significant relationships between speciesrichness and soil type. Silt proved to be the most species-rich topsoil(10–20 cm) in addition to thin soils top of on green- orlimestone bedrock. The variation in species richness due to local relief orform of thesite also showed significant relationships, where flat surfaces had the highestnumber of species. In contrast, no significant relationship was found betweenspecies richness and aspect. Our study suggests that present-day diversitypatterns are much influenced by management history, and that small habitat,e.g., road verges and midfield islets, are important for maintaining speciesrichness.

The Consequences of Road Development in the Golden Gate Highlands National Park, South Africa: Paradise Lost?

The Golden Gate Highlands National Park (GGHNP) was one of the pristine wildlife areas of South Africa until a small dirt road in the park was upgraded in the mid-1990s. The unique environment of the park is a true highland habitat, providing a home to a variety of mammals and birds. As a result of the upgrading of the road through the GGHNP, negative aspects started to impact on the park's natural beauty and tranquillity: firstly, erosion took place in the immediate vicinity of the new road development; and secondly, the traffic through the park increased dramatically. Heavy vehicles, as well as minibus taxis, started to use the shorter route between towns to the east and west of the GGHNP. The uncontrolled collection of grass and wood in the park by the rural population east of the park already poses a big problem. The road is also increasing the potential of poaching in the park.