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During a lifecycle a tyre undergoes degradations due to mechanical wear and chemical ageing which affect not only durability and safety but also tyre/road noise emission and rolling resistance. This paper presents a study with the purpose to study how much tyre/road noise and rolling resistance change when car tyres are worn down from the original 8 mm tread depth to 2 mm, and when chemical ageing of the tyre rubber is simulated by exposure to heat. Six car tyres of different types were selected for the study which were worn on a wear machine in steps of 2 mm tread depth. Before, between and after these wear sessions tyre/road noise and rolling resistance were measured on two drum facilities with different surface textures, including replicas of ISO surfaces. Additionally, coast-by and CPX measurements were made on outdoor ISO test tracks. The results show that the wear and age effect was low on ISO surfaces but dramatic (noise increased with wear) on the rough-textured surface and high but opposite on an extremely smooth surface.
The field of safety in road tunnels has always been an important issue for operators, owners and the responsible authorities. After the tunnel accidents in 1999 the subject gained however in importance. On European level the Directive 2004/54 EC on "Minimum safety requirements for tunnels in the Trans European Road network" has been published. This guideline has to be implemented into national law by all Member States. According to the guideline all Member States of the European Community shall develop a methodology for risk analyses to be applied in certain cases. For Germany, a standardized methodology for a probabilistic quantitative risk assessment has been worked out.
Germany's road infrastructure grew over centuries to become the arteries and lifelines of our society. The present safety of the infrastructure has to be ensured under consideration of environmental aspects. At the same time the owner has to make sure that the maintenance activities are carried out in the most efficient way. Considering the fact that financial resources are restricted, maintenance costs have to be spent in a way to obtain the greatest possible benefit. In the case of bridges, which are one of the most important parts of the road infrastructure in Germany, this task is supported by the application of a bridge management system (BMS). The existing German BMS contains assessment and optimization procedures on object and network level and is the basis for advancements to meet future demands. Developments concern life cycle and quality-oriented, holistically optimized procedures. Reasonable infrastructure management will contribute to meeting efficiency and sustainability objectives and to achieving interoperability. Here holistic network infrastructure management methods are required. There is a strong need for management solutions during the whole service life of a structure. The definition of criteria for evaluation of the relevance of failure mechanisms, including acceptance thresholds, requires the availability of relevant data for management procedure. Tools for innovative investigation methods and an effective data management will help in meeting the requirements. Relevant fields of research are improved maintenance strategies to meet future demands concerning heavy goods traffic, application and further development of nondestructive testing methods for efficient and sustainable management structures, and the improvement of analytic management tools to meet future demands.
At the beginning of the year 2000 the European Commission set the goal to halve the number of road deaths till the year 2010. The main focus are passenger car and lorry traffic. A significant reduction of the accident data could be reached in these groups. The advancement of active vehicle safety systems is an important issue of the programme. The safety of the motorcycle traffic has been disregarded till now. Since 1991 the number of killed motorcycle riders per year has been constant. The number of killed passenger car occupants has been more than halved in the same period. This is why initiatives are caused for the increase of the motorcycle safety. A great safety potential is expected for the Antilock Brake System (ABS). ABS for motorcycles is considered from the economic view in this study. A cost-benefit analysis shall clarify whether the economic benefit of ABS for motorcycles is greater than the consumed resources. Moreover, a sensitivity analysis will determine the maximal justifiable consumption in resource for which ABS is worthwhile. After the sensitivity analysis is done a break-even analysis will determine the market price respectively the annual mileage from which on ABS is worthwhile on user level. For this the fair end consumer market price is calculated which the user is ready to pay. For the considered market prices the annual mileage is determined from which on ABS is worthwhile for the user. The considered time horizon for this analysis are the years 2015 and 2020. For each of these years the accident data is forecasted. At this, it is assumed that the frequency of having an accident per million registered motorcycles decreases based on the present trend. Thus, riding motorcycle gets safer. Hence, the accident data in the years 2015 and 2020 is lower than the accident data today. The cost-benefit analysis is done for each year for four scenarios. Two scenarios handle the market penetration. The first one is the trend scenario, the second one is the mandatory equipment from the year 2010 on. The other scenarios describe the effectiveness of ABS. The effectiveness rates are determined by a literature review. The only potential which can be considered due to the available data is the potential due to an avoiding of the downfall just before the real accident happens. According to this the number of accidents will decrease by 2.4 %. The number of fatalities will decrease by 12.1 %. The number of severe injuries decreases by 11.7 %. However, the number of slight injuries increases by 2.1 %. The mentioned effectiveness rates are valid for the scenarios with the high effectiveness. Even these figures underestimate the actual effectiveness because there are only considered the avoided accidents with downfall. The necessary consumption in resources depends on the produced volume. The more ABS systems are produced, the lower are the costs per system. This is due to realised effects of scale and effects out of learning curves. The system costs depend on the penetration rate. In the trend scenario the system costs for ABS are 120 Euro for the year 2015 respectively 105 Euro for the year 2020. In the mandatory scenario the system costs are 115 Euro for the year 2015 respectively 100 Euro for the year 2020. The benefit-cost ratios are all over the critical barrier of 1.0. Thus, ABS is worthwhile on economic level. In the scenarios with high effectiveness the benefit-cost ratios range between 4.6 and 4.9. Thus, the values are even above the barrier of 3.0. The result of the break-even analysis is that ABS is worthwhile on user level. The considered market prices are 400 Euro in 2015 and 300 Euro in 2020. They are clearly below the determined fair end consumer market prices. The fair end consumer price for the year 2015 is 701 Euro respectively 622 Euro for the year 2020. Thus, ABS is worthwhile for motorcycle riders with an annual mileage higher than 2,200 km (year 2015) respectively 1,900 km (year 2020). The annual mileage of a motorcycle rider is 3,900 km on average. Thus, ABS is worthwhile for most of the motorcycle riders. The mentioned results are valid for the high effectiveness scenarios.