Fordonsbaserade mätningar av meteorologiska parametrar kan ge detaljerad väderinformation från en större täckande yta. Dagens bilar har redan flera monterade sensorer som kan användas för att skapa sådan information, exempelvis temperaturgivare eller vindrutetorkarnas hastighet som ett mått på nederbördsintensitet. Det finns även utrustning som kan monteras in och som efter vissa beräkningar ger däckens friktion mot underlaget. Om mätdata skickas direkt från fordonet till en databas kan väderinformationen tillhandahållas i realtid. I det här projektet utvärderas meteorologisk mätdata från sådana fordonsbaserade sensorer. Mätdata från en leverantör bearbetas och två perioder med mätdata från Göteborgsområdet undersöks. En längre period med mätningar från ett fordon och en kortare period med flera fordon. Den mätdata som används innehåller information om temperaturen och friktionskoefficienten. Arbetet har lett fram till en första metod för databehandling av fordonsbaserad mätdata, då ingen standardiserad metod finns ännu. En statistisk analys görs av mätdatas kvalitet, genom jämförelse med analysmodellen MESAN (Mesoskalig analys) samt genom jämförelse med data från VViS-stationer (VägVäderInformationsSystem). Det görs också en undersökning av korrelationer av temperaturdifferensen mellan fordon och MESAN med olika meteorologiska faktorer. De fordonsbaserade mätningarna har hög korrelation med modellen och stationerna, men visar generellt en högre temperatur. Bildata visar potentiellt också fler meteorologiska detaljer. Temperaturskillnaden är större i Göteborg centrum än utanför, vilket till stor del beror på fenomenet stadsvärmeö som inte representeras explicit i modellen. Temperaturskillnaden är också större vid högre temperaturer, som kan förklaras med vägarnas högre albedo och mindre evapotranspiration jämfört med omgivningen. En klimatologisk kartläggning av friktionskoefficienten har gjorts för månaderna februari till augusti samt för november. I det här arbetet syns inget tydligt samband mellan friktionskoefficienten och andra meteorologiska parametrar. Detta kan bero på den stora mänskliga påverkan på friktionen, exempelvis genom vinterväghållning. För att minska osäkerheten i resultaten krävs mer mätdata både i tid och rum, vilket kan betyda att mätdata från flera leverantörer bör analyseras. Att använda temperaturdata med större noggrannhet ökar potentialen att upptäcka fler och tydligare samband mellan temperaturen och de andra meteorologiska parametrarna som undersöks i den här studien. / Environmental measurements from vehicle-based networks could provide detailed weather information from a greater area. The cars of today already have several sensors that could be used to create such data. For example thermometers and the speed of the windshield wipers as a measure of intensity of precipitation. There also exists sensors that could be mounted on to the car, which after calculations shows the amount of friction between the tires and the ground. If the data were to be sent directly to a database real time weather information could be provided. In this project the meteorological data from such vehicle-based sensores is assessed. Data from one provider is processed and two sets of data from the Gothenburg area in Sweden are analyzed. One set which contains data from a longer time period, with observations from only one vehicle. The other set contains data from a shorter time period with observations from several vehicles. The data collected contains information about air temperature and the coefficient of friction. This project has led to a first method of processing data from vehicle-based measurements, since no such standardized method yet exists. A statistical analysis of the quality of the observations was implemented by means of comparison with the analysis model MESAN (Mesoscale Analysis) and with observations from VViS-stations (VägVäderInformationsSystem). In addition an analysis of the correlation of the temperature difference between the vehicle and MESAN with some meteorological parameters were made. The vehicle-based measurements have a high correlation with the model and the stations but measures higher temperatures in general. The vehicle data potentially also shows more meteorological details. The difference in temperature is larger closer to the center of Gothenburg city than outside, in large part due to the phenomenon called Urban heat island which is not represented explicitly in the model. The temperature differences are also greater at higher temperatures, and can be explained by the higher albedo of the roads and less evapotranspiration compared to the surrounding environment. Climatological mapping of the coefficient of friction during February to August and during November were plotted. In this study no relation between the coefficient of friction and other meteorological parameters were found. This could be due to the human impact on friction, for example through snow clearing. To decrease the uncertaincy of the results more measurements are required both in time and space, which could infer that data from more providers would be needed. To use temperature data with higher accuracy increases the potential of finding more and more evident relations between the temperature and the other meteorological parameters that are analysed in this study.

Abstract Purpose: The issue that this report addresses revolves around sweep-salting of footways and cycleways. More specifically, it focuses on the fact that large differences in elevation can lead to varying land surface temperatures, which, in turn, complicates winter maintenance when using the sweep-salting method. With Jönköping as basis of study, the aim of this report has been to examine the level of knowledge regarding sweepsalting of footways and cycleways in Sweden, this to show optimization possibilities to a developed sweepsalting in Jönköping, taken into account the height differences prevailing in the city.   Method: To obtain data, structured and semi-structured interviews have been carried out. All the interviews have been done and recorded via telephone calls and the interview questions have been emailed to the respondents in advance. The structured interviews have been targeted at four municipalities and the semi-structured interviews have been targeted at two concerned governmental bodies. Parallel to the interviews, three documents have been subject of analysis: Karlstadslaken by Tomas Stomberg, GCM-handboken published by Trafikverket, and Vinterväghållning och expertsystem – en kunskapsöversikt by Magnus Ljungberg. Findings: Sweep-salting as high winter maintenance method is a complicated task. It should be comprehensive, reliable, and conducted hastily over long distances and fairly large areas. It is a relatively new method and knowledge is, as of yet, limited. In the interviews, it became evident that municipalities largely are self-managing in this matter, but that a desire for more intermunicipal collaboration exists. Primarily, municipalities see the need of a governmental framework on how to conduct sweep-salting most efficiently.  De-icing is not carried out the same way in the north of Sweden as it is in the southern parts of the country. In the north of Sweden, the primary focus is snow clearance, and sweep-salting is only carried out when temperatures allow for it. In the south of Sweden, on the other hand, where temperatures often fluctuate around zero degrees Celsius, and snow quantities are manageable, sweep-salting is more prioritized. Implications: Besides keeping track of aerial and land surface temperatures, it is important to control the dew point, in order to apply the appropriate maintenance methods on the most crucial areas of footways and cycleways, at the right time. It is also important to stay updated on municipalities’ development of sweep-salting. Limitations: The economic aspect of sweepsalting is not considered in this study, neither is the perspective from cyclists nor pedestrians of the results of sweepsalting. The study would probably have reached a better result if more municipalities would have been included. Keywords: Brine, DYS spreader, Height difference, Latitudes, PC path, Plate spreader, Surface temperature, Sweepsalting, VVIS Puck.