Measuring friction between the tyres of a vehicle and the road, often and on as many locations on the road network as possible, can be a valuable tool for ensuring traffic safety. Rather than by using specialised equipment for sequential measurements, this can be achieved by using several low-cost measuring devices on vehicles that travel on the road network as part of their daily assignments. The presented work proves the hypothesis that a low cost measuring device can be built and can provide measurement results comparable to those obtained from expensive specialised measuring devices. As a proof of concept, two copies of a prototype device, based on the Raspberry Pi single-board computer, have been developed, built and tested. They use accelerometers to measure vehicle braking deceleration and include a global positioning receiver for obtaining the geolocation of each test. They run custom-developed data acquisition software on the Linux operating system and provide automatic measurement data transfer to a server. The operation is controlled by an intuitive user interface consisting of two illuminated physical pushbuttons. The results show that for braking tests and friction coefficient measurements the developed prototypes compare favourably to a widely used professional vehicle performance computer.

Coating thickness is considered to be one of the most important characteristics of thermally sprayed coatings. Despite this, there is a lack of a measurement method that could evaluate in situ the coating thickness with a sufficient accuracy that could be used as a feedback signal for online, closed-loop control. Offline methods that produce spatially resolved coating thickness measurements by capturing the surface topography have already been demonstrated to provide results with a high accuracy, comparable to the standard reference microscopical measurement method. However, up to now, the approach has not been applied in situ. This paper presents a novel approach to in situ measure spatially resolved coating thickness. It is based on a differential distance measurement of sample thickness before and after applying the coating. A high-resolution 3D camera is used to capture the surface topography and include it in the thickness measurement. The technique provides a 3D view of the deposited coating thickness measured in situ and gives results with excellent accuracy when compared to the reference microscopical method.

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