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The greatest possible safety for vehicle occupants and road users has traditionally been one of the basic values of Mercedes‑Benz commercial vehicles. These values are also consistently applied to buses, as can be seen in a new, recently published guide for emergency services. Its aim is to support emergency services in performing their rescue tactics.
Bus accidents are usually of a much more complex nature than passenger car accidents, due in part to the number of passengers and also to the differing structures of various bus types. Whether urban buses, inter-urban buses or touring coaches are involved, there is a great deal of variation between the models. In addition, technological development has been quite dynamic within the bus industry over the past several years. Besides traditional diesel engines, buses with alternative drives are now increasingly in use. Natural gas and fuel cell drives are also no longer a rarity. Articulated buses provide another challenge which emergency services must handle promptly.
Information on these procedures is available in the brochure, which is divided into detailed sections. When saving lives is at stake, knowing the vehicle-specific access options and how the safety systems function and operate is indispensable. The emergency measures involve numerous risks of injury for the accident victims and their rescuers, whether due to running engines, containers which are under pressure or because of wires, hot water devices, coolant discharge, air conditioning devices, acid, sharp edges, metal parts or shards.
The configuration of the natural gas components in the Citaro CNG is designed for the highest degree of safety. For vehicles with newer construction, the gas supply through an electrical shut-off valve is automatically blocked when the ignition is switched to "Off". Instructions on how to manually cut off the gas supply are included in the guide along with guidelines on extinguishing gas fires in vehicles with fuel cell drive. |
| Avoiding fire hazards: switching off the engine |
The brochure describes what options are available for avoiding fire hazards by switching off the engine. There are various methods available: removing the key from the ignition, or if that isn’t possible, pressing the start/stop button at the driver’s workstation or in the engine compartment. If this option is also inaccessible, the electricity can be cut off using the battery circuit breaker.
But take heed: the battery should only be disconnected from the electric circuit after the power windows, door opener, roof hatch and seat adjustment have already been operated. Using these functions beforehand can allow the emergency services to do their work and rescue occupants much more easily and quickly. When disconnecting the battery, the formation of oxyhydrogen gases must also be anticipated. Another consideration is that most buses have more than one battery. The guide shows exactly where they are located and how to disconnect them.
Another way of switching off the engine is covering the air intake or filling it with CO2 gas to "smother" the engine. A how-to is included in the rescue guide with detailed illustrations and drawings for both urban buses and touring coaches. |
| Safeguards and substructures |
| Stabilising buses which are in an upright or lateral position is relatively straightforward. The vehicle can be secured against tipping or sliding using wheel chocks, supporting struts, cables and belts. An unstable bus or one that is lying on its roof requires extensive supporting materials and possibly a crab. Due to the bus’s heavy weight, the permitted load capacity of the belts must absolutely be respected. |
Lifting the vehicle, when not performed correctly, presents a high risk of injury for the accident victims and the rescuers. Lifting the entire vehicle must generally be done using all the axles. The area on the vehicle between the axles and beneath the sidewall is not suited for lifting or bracing purposes.
If the vehicle is lying on its roof or side, the reinforced perpendicular struts next to the doors and on the opposite side of the vehicle serve as attachment points for belts or endless slings. However, the slings should not simply be pulled through the two opposite windows such that the bus is lifted up by the roof. The roof is not designed to support the bus. That is why the experts at Mercedes‑Benz emphasise the importance of always using the designated lifting points. |
There are various options ways of creating access to the vehicle. First you should check whether the doors can be opened normally using the pneumatic or electrical system. If that doesn’t work, you can use the emergency levers next to the door by following the instructions. However, due to the closing pressure that will still be in effect, you’ll need to ensure the doors do not close again by using wedges or similar objects.
Another way to gain access is by removing the vehicle’s windows or entering through the roof hatch or the gaiter of the articulated joint. But be careful: the front window, which is made of laminated safety glass, can weigh up to 120 kg, and should be secured against falling.
The last access option is enlarging an existing opening with tools to create a rescue opening. However, this should be employed as the last possible option as hidden wires pose an indeterminable risk.
Driver’s workstations in buses are their own complex areas which require exact knowledge and the application of special rescue techniques. If the controls are no longer operational, the rescuers must disconnect the air line according to the manufacturer’s instructions. If the driver is trapped behind the steering wheel, it is often sufficient to remove the lower third of the steering wheel. |
| Partition walls and luggage racks in the passenger compartment |
The passenger compartment following an accident presents an enormous range of challenges to the rescue service. The passenger seats have various fastenings and constructions and there are numerous adjustment options and restraint systems. Grab rails, partition walls and luggage racks can also act as barriers after an accident, making rescue efforts even more difficult. As the aisles in buses are generally relatively narrow, they greatly limit rescue efforts, and it may even be necessary to dismantle passenger seats. It is important to remember that touring coaches also include special areas such as the resting area for the driver or the on-board WC in which additional injured persons may be trapped. There are also dangers to be aware of in the galley, such as short circuits or boiling water.
The new brochure is part of the series "Guides for Emergency Services" from Mercedes‑Benz. You can order it by writing to the e-mail address Info@Mercedes‑Benz-Omnibusse.com. |
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