Measurement techniques

Any new development of a vehicle is only justified if it is characterised by innovations of what has been available so far. Since innovations generally require high technical and financial expenditure for their realisation, it is necessary to ensure by means of tests whether the expected effect (safety, usability, attractiveness, etc.) is actually achieved before a complex production and market offer is realised. The techniques explained in the previous chapter are applied here in practice. The scientific requirements for experiments are defined by the demand for objectivity (the result is independent of test conditions and of the person carrying out the test), reliability (a repetition of the experiment comes to the same result) and validity (it is really measured what is subject of the investigation). An attempt is made to meet these requirements by means of appropriate experimental design. A distinction is made between objective and subjective measurements. The objective measurements include individual anthropometric measures, postures and body movements, contact forces, eye movements, measurements of performance when performing a driving task and the acquisition of physiological parameters. Subjective measurements are characterized by interviewing test subjects. Therefore, fundamental aspects of the so-called psychophysics are explained followed by questions on interview techniques and the creation and use of standardized questionnaires.