This thesis paper presents a simultaneous 3D mapping and geolocation of road surface technique that combines local road surface mapping and global camera localization. The local road surface is generated by structure from motion (SFM) with multiple views and optimized by Bundle Adjustment (BA). A system is developed for the global reconstruction of 3D road surface. Using the system, the proposed technique globally reconstructs 3D road surface by estimating the global camera pose using the Adaptive Extended Kalman Filter (AEKF) and integrates it with local road surface reconstruction techniques. The proposed AEKF-based technique uses image shift as prior. And the camera pose was corrected with the sparse low-accuracy Global Positioning System (GPS) data and digital elevation map (DEM). The AEKF adaptively updates the covariance of uncertainties such that the estimation works well in environment with varying uncertainties. The image capturing system is designed with the camera frame rate being dynamically controlled by vehicle speed read from on-board diagnostics (OBD) for capturing continuous data and helping to remove the effects of moving vehicle shadow from the images with a Random Sample and Consensus (RANSAC) algorithm. The proposed technique is tested in both simulation and field experiment, and compared with similar previous work. The results show that the proposed technique achieves better accuracy than conventional Extended Kalman Filter (EKF) method and achieves smaller translation error than other similar other works. / Master of Science / This thesis paper presents a simultaneous three dimensional (3D) mapping and geolocation of road surface technique that combines local road surface mapping and global camera localization. The local road surface is reconstructed by image processing technique with optimization. And the designed system globally reconstructs 3D road surface by estimating the global camera poses using the proposed Adaptive Extended Kalman Filter (AEKF)-based method and integrates with local road surface reconstructing technique. The camera pose uses image shift as prior, and is corrected with the sparse low-accuracy Global Positioning System (GPS) data and digital elevation map (DEM). The final 3D road surface map with geolocation is generated by combining both local road surface mapping and global localization results. The proposed technique is tested in both simulation and field experiment, and compared with similar previous work. The results show that the proposed technique achieves better accuracy than conventional Extended Kalman Filter (EKF) method and achieves smaller translation error than other similar other works.

Thesis (MScEng)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: Factors influencing surface run-off of bitumen emulsions were studied in order to understand binders for use in the construction of surfacing seals. Run-off of the binder from the road surface causes an inconsistent film thickness leading to ravelling (Johannes, Hanz & Bahia n.d.) and bleeding at the upstream and downstream regions, respectively. There is currently no accepted specification for surface run-off viscosity. Practice mainly relies on empirical tests and experience. As the establishment of such a specification encompasses performance of the binder in various environments or field conditions, this study was undertaken to determine performance of the selected binder. Viscosity was kept constant by spraying the emulsion at a constant temperature and also holding the pavement temperature constant. In order to study the run-off behaviour of the binder, run-off tests were conducted at various gradients, texture depths and spray rates. Surfacing seals of various texture depths were constructed in the laboratory. Using a spray bar, the emulsion was sprayed at various spray rates. The sample surfaces were tilted to various gradients. Results portrayed the effects of the three factors (spray rate, gradient and texture depth) on the amount of runoff. An increase in the magnitude of the factors resulted in a variation in the runoff (increase or decrease). One notable finding was that the runoff from the 9.5 mm seal was less than that from the 13.2 mm seal. The other significant finding was that spray rate had the largest effect on runoff, followed by texture depth, and gradient. / AFRIKAANSE OPSOMMING: Sekere eienskappe wat oppervlakdreinering van bitumen emulsies op paaie beinvloed, is bestudeer om sodoende binders wat gebruik word in die konstruksie van die seëls beter te verstaan. Afloop van die binder vanaf die padoppervlak kan lei tot die vorming van ‘n laag met ongelyke dikte wat moontlike rafeling (Johannes, Hanz & Bahia nd) en bloeing vanuit die onderkant van die pad tot gevolg kan hê. Daar is tans geen aanvaarde spesifikasies wat hierdie verskynsels inperk nie. Konstruksie praktyk berus hoofsaaklik op empiriese toetse en ondervinding. Hierdie studie is dus onderneem om prestasie van die geselekteerde binder vas te stel. Viskositeit was konstant gehou deur die aangewende emulsie en padtemperatuur konstant te hou. Ten einde die afloopgedrag van die binder te bestudeer, is toetse uitgevoer op verskeie hellings, tekstuurdieptes en aanwendingskoerse. Seëls van die verskillende tekstuurdieptes is gebou in die laboratorium, en emulsies op hierdie oppervlaktes aangewend. Die toetsoppervlakte is gekantel om die vereiste helling te kry. Resultate vir die drie faktore wys die invloed op afloop. ‘n Toename in die grootte van die faktore het gelei tot 'n variasie in die afloop (toename of afname). Een noemenswaardige bevinding was dat die afloop van die seël van 9,5 mm minder was as dié van die seël van 13,2 mm. Belangrike bevindinge sluit ook in dat die spuitkoers die grootste invloed het op afloop, gevolg deur die tekstuur diepte en die gradiënt.

Modern day cars are often equipped with a variety of sensors that collect information about the car and its surroundings. The stereo camera is an example of a sensor that in addition to regular images also provides distances to points in its environment. This information can, for example, be used for detecting approaching obstacles and warn the driver if a collision is imminent or even automatically brake the vehicle. Objects that constitute a potential danger are usually located on the road in front of the vehicle which makes the road surface a suitable reference level from which to measure the object's heights. This Master's thesis describes how an estimate of the road surface can be found to in order to make these height measurements. The thesis describes how the large amount of data generated by the stereo camera can be scaled down to a more effective representation in the form of an elevation map. The report discusses a method for relating data from different instances in time using information from the vehicle's motion sensors and shows how this method can be used for temporal filtering of the elevation map. For estimating the road surface two different methods are compared, one that uses a RANSAC-approach to iterate for a good surface model fit and one that uses conditional random fields for modeling the probability of different parts of the elevation map to be part of the road. A way to detect curb lines and how to use them to improve the road surface estimate is shown. Both methods for road classification show good results with a few differences that are discussed towards the end of the report. An example of how the road surface estimate can be used to detect obstacles is also included.

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%.

Manufacturers can develop next-generation production and service for their customers by the data gathered and analyzed from customers’ usage conditions. In this research, the operating condition of articular haulers is collected and analyzed through machine learning algorithms to predict the type of operational topographies and road surface. To achieve that, elevation data and satellite images, which were gathered from Microsoft Azure Maps, are used as data sources to identify the topography and road surface on which machines operated. In the end, two machine learning models are trained with machines’ inclination records and road roughness records, respectively, to classify the topography and road surface. For the topography classifier, the topography is categorized into four terrain labels, including "Low Hills", "Mountains", "Plains", and "Tablelands & High Hills". The road surface is classified into "Paved" and "Unpaved". A Convolutional Neural Network (CNN) image classification model is built for labeling satellite images instead of labeling manually. The results indicate that the prediction for topography labels "Plains" and "Tablelands & High Hills" has superior performance, which accounts for the majority of the raw dataset; on the contrary, the road surface classifier still needs further improvement in the future. In addition, an analysis and discussion regarding the imbalanced dataset are included, and it shows the limited effect on an extremely imbalanced dataset. Finally, the conclusion and future work are given.

Doctor of Philosophy / The control systems installed in modern vehicles lack crucial information regarding the interaction between the tires and the road surface. This knowledge gap significantly impacts the safety and control of the vehicle. Thus, to address this issue, this research introduces a novel fusion approach to estimate friction at the tire-road contact interface. This hybrid fusion friction estimation algorithm employs techniques like signal processing and machine learning, backed up by information from various vehicle and tire dynamics models, to develop algorithms that estimate the level of friction between the tire and the road. This fusion approach enables more precise estimations of the friction coefficient in both normal driving situations and scenarios involving sudden changes in speed or road conditions. Therefore, this research aids in enhancing vehicle safety and control by providing improved information about such tire-road interactions.

Thesis (MScEng)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: Chip and spray surfacing seals has been widely used in South Africa as the preferred surface treatment for rural roads. The design of these seals has also experienced renewed interest and continuous development in several other countries over the past two decades. In South Africa seals are continually used as increasing attention is given to the periodic maintenance of existing surfaced roads. There is also a significant increase in the use of surfacing seals in North America as the need to develop more energy and resource efficient surfacing options becomes a priority. Despite this growing use of surface seals, the seal design and especially the selection of binder type and grade does not always follow scientific processes. Seals are often designed based on client preference, previous experience, material availability and industry trends. With an ageing road network and limited funding to ensure timeous maintenance, the focus in South Africa is moving towards more stringent and scientific design processes. The USA and Europe, forced by increasing traffic volumes and heightened performance demands, are moving towards performance- based specification to account for deficiencies in their current surface seal design methods. One of the major failure mechanisms of surface seals is ravelling which takes place when the binder and the aggregate bond becomes weak and are broken by the forces generated by traffic. This leads to loose aggregate on the road which in turns leads to bare surface patches and broken windscreens. To prevent and address this as part of the development of performance-based specifications, the need for a simple and inexpensive technique for evaluating bitumen and bitumen emulsion bond strength development over time, as well as binder-aggregate compatibility, was identified. Although various tests exist for investigating adhesion between bituminous emulsions and aggregate chips most of the tests does not deliver the level of information required by the performance-based specifications. The Bitumen Bond Strength (BBS) test method was therefore developed with the aim to address some of the limitations encountered in evaluating bond strength between binders and aggregates. The BBS test (AASHTO TP-91, 2011) was developed by the University of Wisconsin – Madison (UWM) in partnership with the University of Ancona – Italy (UAI) and the University of Stellenbosch – South Africa (US) specifically for evaluating bond strength between aggregates and hot applied binders and emulsions, respectively. US became involved in BBS test efforts in 2008 to assist in the development and practical evaluation of the BBS test method. UAI contributed significantly to the development of the test apparatus through their work in conjunction with UWM. Due to time and resources available, the involvement of the US was limited to various discussion sessions, a study tour, the evaluation of the BBS test, and conducting a series of control tests. By using the Bitumen Bond Strength test it was possible to evaluate the practicality and repeatability of the developed procedure and the results measured was successfully used to evaluate the bond strength development of modified and unmodified bitumen emulsions on tillite and granite aggregates. It was also possible to correlate the results achieved at the University of Stellenbosch with results from the University of Wisconsin-Madison due to the fact that testing took place at both institutions. The development of the test and the inter-laboratory test results in essence reinforced the hypothesis that the BBS test protocol can be used to effectively evaluate bond strength of different emulsion types and aggregate types. Except for the loading rate which is a known critical influence, the emulsion type and curing intervals are both identified as the most significant other factors contributing to bond strength development. Aggregate type is also identified as a significant factor that will influence the bond strength development. Interactions between emulsion type and curing interval are identified as the most significant interaction. A lot of further validation test on the BBS test method is still required for the test to be integrated into a performance-based specification system for surface seals. / AFRIKAANSE OPSOMMING: “Chip and Spray” oppervlak seëls is die verkose seël tipe vir gebruik op Suid Afrikaanse plattelandse paaie. Die ontwerp van hierdie tipe seëls is ook tans besig om hernude aandag te trek in heelwat lande. In Suid Afrika word die tipe seël al meer gebruik soos die behoefte na herseël projeke op die verouderde pad netwerk groei . Daar is ook heelwat groei in die gebruik van “Chip en Spray” seëls in Noord Amerika aangesien daar n behoefte is om n meer energie en materiaal effektiewe seëls te gebruik. Ten spyte van die groeiende gebruik van hierdie seëls het daar min wetenskaplike ontwikkeling plaasgevind in the ontwerp daarvan. Seëls word meestal ontwerp gebaseer op klient voorkeur , ondervinding, materiaal beskikbaarheid en ook industrie norms. ‘n Verouderde pad netwerk dwing die Suid Afrikaanse industrie om meer deeglike en wetenskaplike ontwerp prosedures te volg. Die VSA en Europa word deur vinnig groeiende verkeersvolumes en verhoogte kwaliteits behoeftes gedwing om prestasie gebaseerde spesifikasies te ontwikkel. Een van die hoof defekte op seëls is klipverlies wat plaasvind as die verbinding tussen die bitumen en aggregaat verswak en gebreek word deur die kragte wat deur verkeer oorgedra word. Dit lei tot los klip op die pad wat weer tot skade aan voertuie lei. Om dit te voorkom en aan te spreek het die behoefte laat ontwikkel vir n maklike en goedkoop tegniek om te meet hoe sterk die verbinding is wat ontwikkel tussen verskillende bitumen, bitumen emulsies en aggregaat monsters. Alhoewel daar alreeds toetse bestaan wat kan toets hoe sterk die verbinding is , gee die meeste van die toetse nie die informasie wat benodig word deur die voorgestelde prestasie gedrewe spesfikasies nie. Die “Bitumen Bond Strength” (BBS) toets metode is daarom ontwikkel om die tekortkoming in die toets van die bitumen en aggregaat verdindinge aan te spreek. Die BBS toets (AASHTO TP-91, 2011) is ontwikkel by die Universiteit van Wisconsin – Madison (UWM) in vennootskap met die Universiteit van Ancona – Italy (UAI) en die Universiteit van Stellenbosch (US) , spesifiek om die die sterkte van die verbinding wat vorm tussen aggregaat en bitumen te meet. Die US het in 2008 betrokke geraak by die BBS toets studie om hulp te verleen met die ontwikkeling en praktiese evalueering van die BBS toets metode. As gevolg van tyd en personeel tekorte is die betrokkendheid by die US beperk tot verskeie besprekings sessies, n studie toer, die evalueering van die BBS toets sowel as die voltooing van n uitgebreide stel toetse. Deur die voltooing van eksperimente met die BBS toets was dit moontlik om die uitvoerbaarheid en herhaalbaarheid van die ontwikkelde prosedure te toets. Die resultate van die toetse is suksesvol gebruik om die ontwikkeling van die verbinding sterkte tussen gemodifiseerde en ongemodifiseerde bitumen emulsies en tilliet en graniet te definïeer en te evalueer. Dit was ook moontlik om die resultate van die Universiteit Stellenbosch en die Universiteit of Wisconsin-Madison suksesvol met mekaar te vergelyk aangesien toetse by beide die instansies voltooi is. Die ontwikkeling van die toets en die inter laboratorium toets resultate het dit moontlik gemaak om die hipotese te bevestig dat die BBS toets prosedure effektief gebruik kan word om die bitumen en aggregaat verdindinge te toets en te evalueer. Behalwe vir die tempo van die lading waarteen die aftrek sterkte getoets word , is die emulsie tipe en die nabehandeling tydperk beide geidentifiseer as die mees beduidende invloede wat bydrae tot die ontwikkeling van die verbinding sterkte. Die aggregaat tipe is ook geidentifiseer as n belangrike faktor wat die verbinding sterkte ontwikkeling sal beïnvloed. Die interaksie tussen die emulsie tipe en nabehandeling tydperk was geïdentifiseer as die mees beduidende interaksie. Daar sal wel nog heelwat eksperimente voltooi moet word met die BBS toets prosedure voordat dit volkome geïntegreer kan word as deel van n prestasie gebaseerde spesifikasie stelsel vir die ontwerp van seëls.

A smooth surface with good friction on the cycle path is not only important for the traffic safety of the cyclists but also for their comfort and level of service. Potholes, cracks, and bumps are frequent obstructions on the cycle paths. These are all maintenance-related deficiencies associated with the degradation of the structure. In general, the knowledge on degradation of roads is good, as there is a long tradition of investigation into the degradation factors. Cycle paths, even though constructed with similar materials and techniques as the roads, are however not designed in the same way as roads, mainly since they will not be subjected to the same traffic load. Thus, one purpose of this licentiate thesis is to identify degradation factors specific for cycle paths, through a state-of-the-art literature study. The literature review is complemented by two papers, where Paper A analyses the distress found on Swedish municipal cycle paths and Paper B evaluates a novel method for condition assessments on cycle paths related to cycling comfort—the Bicycle Measurement Trailer. The review and papers are meant to act as the basis for the general aim of the PhD-project, namely, to develop more knowledge on the degradation of cycle paths. This knowledge is needed to improve the structural design approaches and maintenance strategies for cycle paths and to give guidance for preventive measures to inhibit degradation. / En slät yta, med god friktion, på cykelbanan är inte bara viktig för cyklisternas trafiksäkerhet, utan för deras komfort och framkomlighet. Potthål, sprickor och ojämnheter är vanliga hinder på cykelvägarna. Dessa underhållsrelaterade brister är direkt kopplade till nedbrytningen av cykelvägarna. Generellt sett är kunskapen om nedbrytning av vägar god då det finns en lång tradition av forskning kring nedbrytningsprocesserna. Cykelvägar, även om de är byggda med liknande material och tekniker som vägarna, är dock inte dimensionerade på samma sätt som vägar då de inte utsätts för samma trafikbelastning. Ett syfte med denna licentiatuppsats är således att identifiera nedbrytningsfaktorer som är specifika för cykelvägar. En ”state-of-the-art” litteraturstudie kompletteras av två artiklar, där Paper A analyserar de skador som återfinns på svenska kommunala cykelvägar och Paper B utvärderar en ny metod, Cykelmätvagnen, för tillståndsbedömningar på cykelvägar, relaterat till cykelkomfort. Litteraturstudien och artiklarna är tänkta att ligga till grund för doktorandprojektets övergripande syfte, nämligen att utveckla mer kunskap om cykelvägars nedbrytning. Denna kunskap behövs för att förbättra de strukturella dimensioneringsprinciperna och underhållsstrategierna för cykelvägar och ge vägledning för förebyggande åtgärder som motverkar deras nedbrytning.

The suspension system in vehicles supports the vehicle's road stability and ride quality by scaling down the vibration responses resulting from road surface's roughness. This research focuses on fatigue life analysis of coil spring component. Static linear analysis is conducted on the 3D model of helical coil spring to investigate deformation and stress responses. Modal analysis evaluates the characteristics of vibration, i.e. natural resonance frequencies and corresponding mode shapes. The stress frequency response is generated after performing the harmonic analysis on the spring. Dynamics and performance of spring are analyzed over practical frequency range of 0 Hz to 200 Hz. Fatigue life estimation of vehicle suspension spring is performed using the stress data obtained from frequency response analysis. The stress-life (S-N) approach is utilized for fatigue life assessment of suspension spring. This durability analysis technique can be utilized in the automotive industry to improve reliability of vehicles. The outcome of this research can contribute in analysis and design of modern smart vehicles. / Master of Science / The suspension system in vehicles supports the vehicle's road stability and ride quality by scaling down the vibration responses resulting from road surface's roughness. This research focuses on the fatigue life analysis of suspension spring component. Initial phase of analysis is conducted to investigate the deformation and stress in 3D model of spring. Dynamics and performance of spring are analyzed over applicable frequency range of 0 Hz to 200 Hz. Fatigue life of vehicle suspension spring is evaluated using stress data from frequency response analysis. This durability analysis technique can be utilized in the automotive industry to improve reliability of vehicles. The outcome of this research can contribute in analysis and design of modern smart vehicles.

Since ancient times, roads have tied people and cultures together. Roads have been createdwith the aim of facilitating trade and cultural exchange among different regions in the world. After the technologic development in vehicle industry and dramatically increase of motoring in the world during the past century road communication has gained a great importance for transporting people and goods. Thus, good safety and accessibility on roads all year round is now a vital necessity for a healthy economy in all modern societies. In order to keep roads safe, available for use with high transport quality they need to be maintained in real time. One of the most difficult tasks in this context is to keep the roads in good condition and accessible even during winter. The main objective of this doctoral thesis is to attempt to specify the most efficient ways of executing winter road maintenance.  The preliminary issue in this context is whether it is the use of current assistive tools, that is, technical aspects that should be optimized and developed or whether it is the way in which winter maintenance services are procured and outsourced, that is, contractual aspects that should be improved which could give the optimal impact for both clients and contractors and make winter road maintenance more effective, or both issues. In order to define the outline of the research project a comprehensive state of the art survey was initiated with the intention of collecting and gaining insights into the earlier studies in the research area. Three basic areas associated with the performance of winter road maintenance were considered to be most relevant for review due to the anchorage between the areas. The selected areas were climatological, technical and contractual aspects. The literature review was followed by an electronic questionnaire survey. The results of the study in this stage showed that current technical methods almost functioned in a reasonable manner but there was an imprecise dissatisfaction with the current maintenance contract. The second stage of the research consisted of a number of additional empirical investigations in order to identify contractual problematic issues behind the current winter road maintenance in Sweden. Generally, those factors that are rarely considered as potential underlying causes to costly performance of winter road maintenance in Sweden were studied in this research project for example improper use of related technical assistive tools, procurement of improper bundled winter services and inappropriate contract structure. This thesis consists of six papers, five of which are related to each other, and the first one is completely independent but within research area. Findings in the thesis contributes to extend understanding about; how designing appropriate contracts can improve winter road maintenance, how proper use of assistive tools can reduce unnecessary winter road maintenance costs and minimize road traffic disruptions and delays, how a partnering structure in contracts can create confidence and trust between clients and contractors that in turn leads to minimizing or eliminating conflicts and disputes between parties involved, how choice of appropriate procurement methods through proper bundling of winter road services can contribute to shorten the procurement process and create incentives for contractors, and how selection of proper payment mechanisms can contribute to higher service quality of performed winter road measures. Additionally, an adequate knowledge and understanding of climate, proper knowledge of road weather and its impact on winter road traffic is essential for contribution of better planning of how to maintain the road network during winter. Since understanding about winter issues and its effect on winter road traffic is far from complete and winter road maintenance in the cold regions is a similar challenge, broad and complex, the results of this research may even contribute to improving winter maintenance problems in the countries with severe winters like Sweden. / <p>QC 20140227</p>