Underrun protection (commercial vehicle)
An underride protection is for road safety -relevant component of a utility vehicle and designed to prevent that, in a road traffic accident smaller vehicles (cars, bicycles) the structures, wheels or the chassis of a larger lorry or trailer from the front or drive behind the road users are injured or killed . Lateral protection devices on the long sides of the vehicle fulfill this function, also for pedestrians.
General
Due to the design, the chassis of a larger truck or trailer is much higher above the road surface than that of a passenger car. In a collision, two vehicles, which are very different in structure and mass , come together. In the event of a collision, the truck or trailer can be driven under, even at low speed. The windshield of the car can be broken through and massive parts of the truck such as loading sill or superstructures penetrate into the passenger compartment. The A-pillars supporting the window and the roof structure of the car also offer little protection for the occupants. Underrun protection on larger trucks and trailers is therefore required by legal regulations across Europe.
The task of the underrun protection is also to provide an abutment for the energy-absorbing areas of the body of the colliding vehicle (also known as crumple zones ) so that the energy of the collision can be dissipated.
construction
An underrun protection consists of a cross member made of metal, which, like a bumper , covers almost the entire width of the vehicle. It consists either of steel or aluminum: Folded steel profiles are characterized by a higher resistance and are inexpensive, however, tend - amplified by the pressure generated by the rear wheels rockfall - for corrosion ; Aluminum, on the other hand, is more expensive, but non-corroding and has a lower mass. This cross member is connected to the chassis of the truck or trailer via steel fasteners.
The rear underrun protection is often used to accommodate the tail lights and the license plate including the license plate light . In addition, the protective space in front of the rear underrun protection is often used to accommodate components that have to be easily accessible, but whose installation on the chassis causes space problems: for example, the 110 kg traction battery including power electronics is installed there in the MB Atego Hybrid .
Legal regulations
Rear underrun protection
In the area of the European Union , several EC directives stipulate the construction, mounting heights, dimensions and test conditions of the rear underrun protection in detail. In Germany, these regulations are implemented by § 32b of the Road Traffic Licensing Regulations (StVZO), which was introduced with the ordinance amending the Road Traffic Licensing Regulations of June 20, 1973 and initially for everyone from January 1, 1975 for the first time in vehicles and trailers coming into traffic.
According to this, a rear underrun protection is generally required for all vehicles and trailers where the chassis is more than 55 cm above the road or the distance between the end of the vehicle and the rear axle is more than one meter.
No underrun protection is required for agricultural and forestry tractors , work machines, semitrailer tractors (which anyway mostly drive with a coupled semitrailer ) and certain trailers. Vehicles for which such a component does not appear to be required due to their intended use (e.g. vehicles for garbage disposal ) or which are often used off public roads and in the field, such as certain construction or military vehicles, are exempt from the regulation ( Section 32b Para. 3 StVZO).
Vehicles that are equipped with a tail lift must also be equipped with an underrun protection device. This may be interrupted due to the carrying mechanism and thus be in several parts.
Front underrun protection
In order to better protect the occupants of cars, smaller commercial vehicles and cyclists even in frontal collisions with heavy trucks, since 2003 all trucks across Europe with a gross vehicle weight of more than 3.5 t must also be provided with a front underrun protection ( Section 32b (4) StVZO) ; the regulation provides for exceptions. Detailed specifications with regard to the mounting heights and dimensions are specified in EU directives and ECE regulations .
Side guards
Larger trucks and trailers (with a permissible total weight over 3.5 t) must also be equipped with side protection devices. These devices should not only make it difficult to drive under; rather, the aim is to prevent pedestrians, cyclists and motorcyclists from getting under the vehicle and being run over by the wheels. The outer surfaces must be smooth and as continuous as possible from front to back. Detailed specifications regarding the mounting heights and dimensions are determined by ECE regulations . In Germany, these regulations are implemented by Section 32c of the Road Traffic Licensing Regulations (StVZO).
Further development
As early as 2000, studies by the German Insurance Association indicated that the current protection systems sometimes do not offer sufficient resistance in the event of a rear-end collision. Depending on the course of the collision and the impact speed, the underrun protection can tear off.
Another problem is the required installation height of the underrun protection: The currently prescribed installation height on the truck (55 cm above the road) is offset by the lower car frame support (approx. 40 cm above the road). This situation, which is unfavorable for the car, is additionally worsened because the front of the car tilts downwards when braking sharply (see brake pitching ), which makes it easier to drive under the underrun protection. A wedge shape of the car hood due to aerodynamics is also a disadvantage here.
A further complicating factor is that the car's protective systems do not always trigger adequately if the vehicle is driven under: For example, depending on the change in relative speed , front airbags do not recognize every drive under as a severe impact.
All investigations lead to the recommendation to lay the underrun protection 10 to 15 cm lower and to reinforce the construction so that the profiles do not break away in a rear-end collision.
According to rough estimates from the year 2000, these measures could prevent the death of around 100 road users each year in the EU and reduce the severity of injuries for a further 600 seriously injured drivers. These demands are also supported by the automobile associations.
On the other hand, if the underrun protection is installed too low when driving on a ramp, this component may touch down and be destroyed due to the lack of ground clearance . Ramps are often used on the premises of haulage companies or for entering double-decker ferries .
The European Commission has recognized the need to change the legal norm ; However, experience has shown that procedures in European legislation can be expected to take a long time to introduce. Nevertheless, problem-solving in-house developments such as the Safeliner are already available.
Mansfield bar
On July 29, 1967, there was a rear-end collision in Louisiana , (USA) in which the then very popular film actress Jayne Mansfield was killed. Her car got under a slowly moving tractor - trailer . The accident also received considerable media attention because the actress was beheaded according to initial reports, which is a not uncommon occurrence in this type of accident (in later reports it was pointed out that her head was not severed and that in the police photos only a wig or parts of her Scalp were visible.). The spectacular accident quickly led to the introduction of underrun protection for all semi-trailers by the National Highway Traffic Safety Administration . This is still known today in the USA as the Mansfield bar (sometimes also as the DOT bumper ).
See also
Web links
- Section 32b of the Road Traffic Licensing Regulations (StVZO) rear and front underrun protection
- Section 32c of the Road Traffic Licensing Regulations (StVZO) Lateral protective devices
Individual evidence
- ↑ Council Directive 70/221 / EEC of March 20, 1970 on the approximation of the laws of the Member States relating to containers for liquid fuel and underrun protection for motor vehicles and motor vehicle trailers . Directive on underrun protection of March 20, 1979.
- ↑ Directive 79/490 / EEC of the Commission of April 18, 1979 for the adaptation of Directive 70/221 / EEC of the Council on the harmonization of the legal provisions of the member states on containers for liquid fuel and underrun protection of motor vehicles and motor vehicle trailers to technical progress . Directive on underrun protection of April 18, 1979.
- ↑ Directive 2006/20 / EC of the Commission of February 17, 2006 on the adaptation of Directive 70 / EC / EEC of the Council on fuel tanks and underrun protection for motor vehicles and motor vehicle trailers to technical progress . Directive 2006/20 / EC of February 17, 2006, No. 3 of the annex. Retrieved April 14, 2013.
- ↑ Directive 89/297 / EEC of the Council of April 13, 1989 on the approximation of the laws of the member states on side protection devices (side protection) of certain motor vehicles and motor vehicle trailers . In: EUR-Lex . Retrieved April 6, 2013.
- ↑ Regulation No. 93 of the United Nations Economic Commission for Europe (UN / ECE) - Uniform conditions for the approval of devices for front underrun protection In: Official Journal of the European Union . July 17, 2010, accessed April 7, 2013.
- ↑ Regulation No. 73 of the United Nations Economic Commission for Europe (UN / ECE) - Uniform conditions for the approval of vehicles with regard to their side protection devices. dated December 9, 2010.
- ↑ Rear underride protection for commercial vehicles. ( Memento of the original from July 9, 2011 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. (PDF; 2.6 MB) GDV effectiveness study from 2001. Accessed on April 28, 2013.
- ↑ ADAC Accident Research. (PDF; 228 KB) ADAC Accident Research reports from March 2011, p. 5. Accessed on April 7, 2013.
- ↑ The truck in the current accident situation ... ( Memento of the original from July 9, 2011 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. (PDF; 2.4 MB) GDV accident research from December 2000. Retrieved on April 28, 2013.
- ↑ Underride protection for trucks: ADAC calls for improvements to the EU directive. ATZ website from December 13, 2012. Accessed April 21, 2013.
- ↑ Standard protection can be fatal Website of the ADAC. Retrieved April 21, 2013.
- ↑ Crash protection measures website of the European Commission . Retrieved April 6, 2013.
- ↑ Safeliner. Website of the engineering office Schimmelpfennig + Becke . Retrieved April 28, 2012.
- ↑ Jayne Mansfield. In: Snopes.com. January 3, 2001, accessed December 13, 2006 .
- ↑ Underride guard. Private website everything2, October 8, 2004. Retrieved April 6, 2013.
