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A changed attitude to environmental concerns together with rising fuel prices has resulted in an increasing demand for alternative forms of fuel for vehicle propulsion. In particular, the registration figures for vehicles powered with compressed natural gas (CNG) and liquefied petroleum gas (LPG) show strong growth rates in Europe. Both vehicles originally equipped by the manufacturer and those which are retrofitted are very common. To find out more about the technical- and fire safety of retrofitted cars DEKRA Accident Research carried out a crash test in accordance with FMVSS 301. The results were used to prepare a guide for rescue services.

The objective of the presented research is to analyze the cause-and-effect chain of the emergence of tire marks and to indentify how the intensity of a friction-related tire mark on asphalt or concrete pavements can provide additional information related to forces or slips at the marking wheels. Focusing on tire marks due to abrasive wear, the influences on the intensity of tire marks are analyzed based on three categories: vehicle dynamic parameters, tire and road properties, which determine the sensitivity of tire marking for a specific tire-road combination for constant vehicle dynamic parameters; and optical parameters, influencing the contrast of a given tire mark. The analysis includes a new objective method for the assessment of the tire mark intensities derived by photos of tire marks, generated with a tire measurement trailer. Additionally a test rig was developed to determine the tire marking sensitivity with reference marks under controlled friction conditions.

Secondary safety systems to protect occupants have attained a very high level over the past decades. Further improvements are still possible, but increasingly minor progress is only to be had with a high degree of effort. Today, integrated safety is the key aspect to improve overall safety in manifold accident situations. This is already implemented in the development of new cars. But so far, the testing and assessment of new cars still involves using tests which do not take into account the significant additional potential of integrated safety measures. An example is given with automatic pre-crash braking functions, which are newly available in state-of-the-art cars. Using reliable information on an imminent crash, such measures act already in the pre-crash phase and can result in a significantly high decrease of the accident outcomes. Such preventive measures are the key to a further substantial reduction of the figures of crash victims on our roads.

SAE paper 2013-01-0213 [1] described firefighting tests with Li-Ion traction batteries. However, additional knowledge and experience has been gained since then. In 2018 and 2019, DEKRA Accident Research and the Department of Anesthesiology of the University Medical Center Göttingen conducted crash tests far beyond standard with four battery electric vehicles. Three of the vehicles’ batteries were used to test a new method of firefighting. A specially designed lance was used to pierce the battery housing, which enabled water to be directly fed into the housings themselves. The method proved to be very effective, but the tests also showed some limitations. The information gleaned from this series of tests and experience gained from other tests was used as a basis for the formation of a multidisciplinary group of experts.

Tire mark analysis is an important factor in accident reconstruction. A precise determination of pre- and postcrash speeds as well as longitudinal and lateral accelerations from tire marks contributes significantly to a reliable accident reconstruction. Continuous advancements in tire and vehicle technology – in particular with respect to modern control systems such as anti-lock braking systems (ABS) – raises the question what role tire marks play in accident reconstruction today. Moreover, this accompanies the question to what extent potential interventions by vehicle control systems such as the electronic stability program (ESP®) resp. the electronic stability control (ESC) can be identified in a tire mark. The widespread use of these systems today makes them increasingly important in accident reconstruction.