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New vehicle types are extensively tested to check almost all factors that influence ride and handling. With reference to the Association of German Car Tuners" (VDAT e.V.) valuations, approximately 10% of all cars in Germany are being modified by their owners. 28 % of those modifications" sales are divergent wheel-tire combinations, 13 % are tuning measures on the chassis suspension or wheel spacers. In almost all cases the singular modifications present a general permission for specific vehicles they have been tested in. Combined tuning measures, however, are often checked by just one inspector, following a procedure of mostly subjective assessment criteria. Today, critical attributes are only being observed, in case a vehicle is involved in an accident and the modifications are identified as crash causal factors or as a cofactor on the development of a crash. For the first time, a field study allows a survey of safety affecting chassis modifications. The test layout has to comply with some basic conditions. Different vehicle concepts with a wide margin of modifications are required to get a high transferability of the results. A total amount of more than 150 tested vehicles serves the same purpose. The tests are limited concerning the installation time of measurement techniques and the requirement that no damage, defilement or immoderate wear of the vehicles are accepted by their owners. Due to such factors as well as the driver Ìs acceptance, the vehicles are controlled by its owners instead of robots or test drivers. For keeping down the driver- influence, the lane has narrow boundaries and the driver has to drive in strictly adherence to the given instructions. After gathering all modifications, as well as static and kinematic parameters like the toe and camber angle, dynamic testing of predominantly lateral dynamics is conducted. Besides standardized tests like the ISO 3888-2 (Obstacle Avoidance) or the ISO 14512 (Braking on Surfaces with Split Coefficient of Friction), to test the influence of modified kingpin offsets caused by wheel spacers, some deviant tests are conducted. Those are required due to the demand of objective test results for road tests with vertical induced stimulation of the chassis suspension. Hence, new tests on corner braking with and without vertical stimulation have been developed. The interpretation of data includes thresholds, e.g. the maximum entrance velocity without hitting cones, on the one hand, and the analysis of characteristics of data concerning time and frequency range, "1-second values" and peak response times on the other hand. Besides the thresholds as indicators for the achievable velocities, which are mainly affected by friction coefficients, the vehicle reaction in the course of time characterizes the vehicle reaction in the threshold range and consequently the operational demands on the driver. The field study has started and promises the first long-range analysis of chassis modifications. The results offer a basis for hypothesis and resultant further test layouts for oncoming studies of the identified critical tuning measures.
In the last years there has been a decline in accident figures in Germany especially for four wheeled vehicles. At the same time, accident figures for motorcycles remained nearly constant. About 17 % of road traffic fatalities in the year 2006 were motorcyclists. 33 % of these riders were killed in single vehicle crashes. This leads to the conclusion that improving driving dynamics and driving stability of powered two wheelers would yield considerable safety gains. However, the well-known measures for cars and trucks with their proven effectiveness cannot be transferred easily to motorcycles. Therefore studies were carried out to examine the safety potential of Anti Lock Braking Systems (ABS) and Vehicle Stability Control (VSC) for motorcycles by means of accident analysis, driving tests and economical as well as technical assessment of the systems. With regard to ABS, test persons were assigned braking tasks (straight and in-curve) with five different brake systems with and without ABS. Stopping distances as well as stress and strain on the riders were measured for 9 test riders who completed 105 braking manoeuvres each. Knowing the ability of ABS to avoid falls during braking in advance of a crash and taking into account the system costs, a cost benefit analysis for ABS for motorcycles was carried out for different market penetration of ABS, i.e. equipment rates, and different time horizons. The potential of VSC for motorcycles was estimated in two steps. First the kinds of accidents that could be prevented by such a system at all have been analysed. For these accident configurations, simulations and driving tests were then performed to determine if a VSC was able to detect the critical driving situation and if it was technically possible to implement an actuator which would help to stabilise the critical situation.