Näringslivet efterfrågar ett införande av 74 tons lastbilar på det statliga vägnätet. Det finns ett flertal fördelar med att höja maximala bruttovikten från nuvarande 64 till 74 ton. Däremot är höga bruttovikter direkt kopplade till bärighetsrelaterade skador. Syftet med denna studie är att ligga till grund för vidare arbete av Trafikverket. Detta för att uppnå bättre kontroll på hela det statliga vägnätet och den tunga trafikens inverkan. Studien har utgått från observationer i PMSv3, ett webbaserat system med grafiska tvärprofiler baserade på vägytemätning samt information om det statliga belagda vägnätet. Observationerna innefattar mönsteridentifiering av återkommande tvärprofilstyper tillskrivna skador av den tunga trafiken. Resultatet av tvärprofilstyperna har sedan analyserats och beskrivits som representativa spårtyper för det statliga vägnätet. Slutsatsen är att det finns indikation på mönster av spårtyper. Utifrån observationerna i PMSv3 har spårtyperna formulerats som hypoteser för vidare forskning. / The wood industry asks for an imposition of 74-ton trucks on the national road system. There are several advantages of increasing the maximum gross weight from 64 to 74 tons. On the other hand, high gross weights are directly connected to structural road damage. The purpose of this study is to serve as foundation for further research by the Swedish transport administration. The ulterior goal is to reach better control on the national road system. The basis of the study is a web-based system - PMSv3, which contain road information and transverse road profiles. The observations in PMSv3 have led to rut-types ascribed due to heavy gross weights. The conclusion is that rut-patterns indications exist. Based on the observations in PMSv3, the rut-types have been formulated as hypothesis for further research.

Autonomous driving technology is now evolving at an unprecedented speed. HD maps, which are embedded with highly precise and detailed road spatial and object information, play an important role in supporting autonomous vehicles. This thesis presents the development of a semi-automated HD map creation and updating method that is capable of extracting basic road feature information to HD maps by employing raw MLS point cloud data. The proposed HD map creation method consists of four steps: Road edge extraction, road surface extraction, road marking extraction and driving line generation. First, an existing curb-based road edge detection method is applied to extract road edge candidate points according to the elevation difference and slope between points. This thesis develops an edge vectorization algorithm based on the point's distance-to-trajectory. Then, the road surface is extracted by filtering the points inside fitted edges on the XY plane within a range of the ground elevation. In the next step, instead of using intensity to detect road markings used by most studies, this thesis fuses point clouds and images to assign each point with an RGB value to segment marking points. Marking objects are extracted by conditional Euclidean clustering and classified according to a manually defined decision tree. Finally, driving lines are generated based on the vectorized road edge and lane markings. The HD map update method varies depending on which data source is updated for the road segments, including updating images only, updating point clouds only and updating both images and point clouds. The method is evaluated by six point clouds and image datasets collected from different types of roads. The extracted road edges are assessed by both length- and buffer-based assessment methods. The results indicate that the road edge extraction algorithm performs well in all three dimensions. The road surface extraction results confirm the high accuracy of extracted edges. In addition, the quantitative evaluations of road markings demonstrate that the proposed road marking extraction method achieves an average recall, precision, and F1-score of 94.50%, 81.65% and 87.09%.

Roads are long linear features on the landscape that impact wildlife and their habitats. Among all forms of wildlife turtles are one of the most negatively affected by roads. Wildlife biologists and civil engineers have developed and implemented road design measures to mitigate the negative effects associated with roads. One common approach used to reduce road mortality and to facilitate movement of turtles is to construct a road mitigation system. There are currently 28 road mitigation systems for wildlife in Massachusetts, of which 14 were specifically built for turtles. We identified all known systems in Massachusetts and collected site and structural design information for each. In addition, we also examined the relative effectiveness of experimental passages for freshwater turtles. Structures were evaluated with respect to how their height, width, and position (at or below-grade), influenced the movements of painted turtles. A total of 190 turtles were exposed to the experiential trials and their behavior was characterized by 3 response variables (Total time to complete the trial, Total hesitations observed, and Success based on no hesitations and completion of the trial in less than 120 minutes). We concluded that painted turtles exposed to below-grade tunnels were less hesitant and traveled faster through them as the tunnel size increased from 0.6 m x 0.6 m to 1.2 m x 1.2 m. The 1.2 m x 1.2 m tunnel size overall proved to be the size with the fewest hesitations observed, fastest total times, and highest success rate.

No description available.

Call number: LD2668 .T4 1962 C37

This thesis derives and validates Performance Indicators for Safe Mobility for Older Road Users in Urban Areas. Performance Indicators are objective, auditable parameters, which when used as a set can provide additional information to decision-makers about the operation of the transport system. Great Britain, in common with many countries across Europe has an ageing population. The proportion of older people who hold a driving licence and have the use of a car is also expected to rise, with future generations of older people travelling further and more frequently than previous generations. Older road users are already over-represented in traffic fatalities, particularly in urban areas. Measures to protect older road users from risk in traffic will be of crucial importance as the population ages. However, against this background the need remains for them to access key facilities such as shops, leisure activities and health care. Maintaining independent mobility is essential in maintaining mental and physical health. Traditionally, outcomes-based measures such as accident or casualty figures have been used to monitor road safety. Techniques such as hotspot analysis have identified locations on the road network where accident numbers are high, allowing modifications to road infrastructure to be designed and implemented. Using outcomes measures alone however, it is difficult to ascribe improvements in accident or casualty figures to particular policy interventions. Moreover, the effect of road safety interventions on other related policy areas mobility being one is impossible to assess without access to detailed, disaggregated exposure data. To make fully informed policy decisions about infrastructure design and how it affects older users, a better understanding of the linkages between safety and mobility is required. Performance Indicators offer the possibility to look at these linked policy objectives within a single framework. Focus group data was used in conjunction with the results of previous studies to identify the infrastructure features which present a barrier to older users safe mobility in urban areas. These included factors which increased risk, such as wide carriageways, complex junctions and fast-moving traffic, and factors which hindered mobility, such as uneven or poorly maintained pavements, poor lighting and traffic intrusion. A thematic audit of infrastructure in a case study city (Coventry) was undertaken, in order that the incidence of such infrastructure could be recorded. It was found that in many areas of the city, safe mobility for older road users was not well provided for, with the majority of locations having barriers to safety and/or mobility for both drivers and pedestrians. The audit data was then used to calculate a set of Performance Indicators, presented via spider graphs, which describe the degree to which the infrastructure caters for the safety and mobility of older drivers and pedestrians. The spider graphs allow for easy comparisons between the different geographical areas, and also between the different policy areas, allowing policy priorities to be identified. The calculated Performance Indicators were validated using case studies collected from the focus group participants. The case studies identified features that affected travel habits by causing a change of route or change of mode, providing evidence of the link between infrastructure design and safe mobility for older users. The results of the Performance Indicator analysis were then compared to accident figures, in order to identify differences between the two approaches, and to understand what policy implications would result from a monitoring framework that used Performance Indicators for safe mobility, rather than outcomes-based measures alone. One implication of the Performance Indicator approach is that it may identify different areas for priority action from those identified by accident or casualty figures. A location which does not have high accident numbers may nevertheless perform poorly on a Safety Performance Indicator measure. This is because older users who feel at risk make different route or mode choices to avoid the infrastructure, the lower accident rate being explained by lower exposure to risk. Conversely, measures to promote independent mobility for older users may increase their accident involvement, not because the environment becomes more risky, but because the exposure of older users to risk increases, because they are willing and able to walk or drive in an area they previously avoided. The thesis concludes that infrastructure design does not currently cater well for the needs of older pedestrians and drivers, and that a framework which incorporated Performance Indicators could make more explicit the trade-offs between safety and mobility, and between different categories of user. This additional information would enable policy makers and practitioners to make more informed decisions about how to prioritise competing objectives in complex urban areas.

published_or_final_version / Urban Planning and Design / Master / Master of Science in Urban Planning

Road traffic networks offer a particularly challenging research subject to the control community. The traffic congestion around big cities is constantly increasing and is now becoming a major problem. However, the dynamics of a road network exhibit some complex behaviours such as nonlinearities, delays and saturation effects that prevent the use of some classical control algorithms. This thesis presents different models and control algorithms used for road traffic networks. The dynamics are represented using a "fluid-flow" approach. This leads to a system of quasi-linear hyperbolic partial differential equations which represents the behaviour of the drivers on each road. The boundary conditions are represented by a set of algebraic relations describing the behaviour of the drivers at the junctions. Two models with different complexities are introduced and their properties analysed. Different control algorithms are presented. One method is focused on the steady state case and intends to minimise a "sustainable cost" function. This function takes into account a time cost, the pollution and the accident risk. Two other methods which are able to deal with transient effects are also presented. The first one is a routing strategy expressing how to spread the traffic flow between two paths leading to the same destination. The second one is a ramp metering strategy using linear feedback.

No description available.

No description available.