VC-Compat Final Technical Report


VC-Compat Final Technical Report in PDF

Car to truck impact results

For car to truck impact the benefit of energy absorbing front underrun protection devices over the current legislative (‘rigid’) devices in Europe (EU15) was estimated to be around 160 lives saved and around 1200 seriously injured casualties mitigated per year. The analysis used an accident data set in which the vast majority of the trucks was not fitted with rigid FUPs as currently mandated by directive 2000/40/EC (ECE Regulation 93). Hence, assumptions had to be made to account for the effect of fitting rigid FUPs. Related to car to truck rear end collisions, an appropriate RUP device would save around 150 lives and mitigate around 1800 seriously injured casualties per year. The cost of energy absorbing FUP structures and improved RUP structures was estimated as cost to modify a current structure which fulfils the current legislation. The additional cost for an energy absorbing FUP is 100 – 200 Euro, and for an improved RUP between 100 – 250 Euro or even more if an adjustable device is required. A programme of seven car to truck full scale tests was performed with rigid and energy absorbing FUPs. In all the tests underride was prevented, even at closing speeds of 75 km/h. The first four tests showed poor structural interaction with the car’s front structure. This was thought to be the reason why the energy absorbing capability on the truck was not properly activated because in a similar test with a different car, recommended by the car leg of the project for its better structural interaction potential, the FUP’s energy absorption was activated. However, the energy absorber in this test was prevented from collapsing freely and absorbing energy as designed. So, to generate baseline data to show the benefit of an energy absorbing FUP compared to a rigid FUP, a special FUP was designed with a different energy absorption structure than a standard e.a. FUP. Tests with this FUP in a rigid and energy absorbing mode showed a significant improvement in the car’s crash performance for the energy absorbing mode, but not the level of improvement that would be necessary to give the benefit required to justify the introduction of a regulatory test. However, although the benefit of energy absorption by the FUP was not unambiguously proved with the tests performed, the EC project officer requested continuation of the project to develop test/evaluation procedures for e.a. FUPs as planned, rather than redirection to perform additional baseline tests. In response to this, a number of test procedures to assess e.a. FUPs with different levels of complexity/simplification were defined and investigated regarding their advantages and disadvantages compared to a full scale passenger car test. The procedures investigated were numerical simulation, quasi-static, and dynamic procedures using rigid and deformable impactors. The deformable impactor used was the Progressive Deformable Barrier (PDB), also used in the car to car leg. A definite decision for a final test procedure with performance criteria could not be made, simply because the supporting data from baseline tests were missing. However, all tests have the potential to be used as a final procedure in assessing energy absorbing front underrun protection structures on trucks. To obtain more data, more full scale tests with different types of vehicles and trucks with energy absorbing FUPs with greater energy absorbing capability are needed. Moreover, the amount of energy which can be absorbed underneath the truck without causing too much underride is limited. And also, the energy absorbing capability and capacity of passenger car front structures has improved to such an extend that impact speeds up to 64 – 75 km/h may well be survivable for passenger car occupants in collision with rigid FUPs. This means that additional structural deformation in the front of trucks may be necessary to achieve the benefits originally expected from energy absorbing FUPs to increase the energy absorbing capacity without permitting too much underrun. For rear underrun, accident data and crash tests show that current rear underrun protection devices as required by present legislation are inadequate for collisions of modern passenger cars into the rear end of a truck/trailer with closing speeds greater than 50 km/h. In this project the properties of an improved RUP structure were determined and tested to prevent impacting passenger cars from underrunning the truck/trailer at speeds up to at least 56 km/h. From this work, recommendations for amendments to be implemented in directive 70/221/EEC (including amendment 2006/20/EG) and ECE Regulation 58 are made. However, it should be noted that the project has only considered amendments to the requirement for vehicles of maximum GVW. Lighter trucks are currently permitted to have reduced test load requirements and the validity of these lower test loads has not been assessed, so further work is needed to do this.