Vehicles and visibility
It is important that the driver of a vehicle can see all around his vehicle, whether it be large or small. Many accidents have occurred where vehicles have reversed into each other, reversed over edges, where small vehicles and large vehicles collide when the small vehicle is over taking, or cuts in front of the large vehicle. Some dump trucks cannot see something 1.8 m high twenty metres in front of the truck. For this reason small vehicles should be highly visible like this land rover with light clusters, flashing mast, and colours that are distinctive against in this case a dark back ground and they should always have side windows for extra visibility.
The video illustrates why it is necessary to have good all round visibility on machines. By use of combination mirrors and CCTV it is possible to see a 1m pole 1m around most machines.
This illustrates the poor vision to the front and sides of a normal dump truck. Most utility vehicles are the same height as a 6 foot man.
This illustrates the distance that a driver cannot see on a normal truck. It is important that any small vehicles also have good all round visibility and vehicles such as site 4X4's should be equipped with side windows.
The visibility is reduced as vehicle come over brows of hills. The driver should always be able to see his stopping distance. Proper design of haul roads will eliminate this problem or speed restrictions will have to be put in place.
The following video clip shows how important good visibility is around vehicles. The visibility must be such that the vehicle can be used in complete safety for both the driver and any exposed person. A common mistake is to think that by removing the pedestrians all will be well. Not only is this often impractical but it does nothing to secure the safety of the driver. The areas of concern are to the front, sides and rear of the machine. The video shows two average size vehicles parked at the front and rear of an average sized wheel loader. The blind areas are shown in red. Looking from inside the loader, the top of the front vehicle can be seen but to the rear you cannot see any vehicle. By adding a rear view mirror you still cannot see the rear vehicle. But by fitting a cctv the rear blind area has virtually been eliminated. But partially raising the front bucket means you can no longer see the vehicle at the front. Raising the bucket means you now have restricted vision forwards but you cannot see in the distance.The improvement in visibility is a combination of improved vehicle design, fitting appropriate aids such as mirrors ( particularly modern combination mirrors ) and cctv to give adequate visibility to the sides and rear and work place layout. On dumptrucks there are similar problems to the front, sides and rear. The video shows how easy it is to reverse over a small utility vehicle in this simulation with a car.
This loading shovel was fitted with an oversize coaling bucket. The driver could not drive it with the bucket down because he was unable to see a pedestrian over the top of it. He therefore drove with it raised. The visibility was so bad that he collided with a 50 tonne truck slicing through the cab.
The visibility when driving a loading shovel with the bucket raised is very poor. For this reason it is not recommended that loading shovels are used as lifting machines, unless the bucket is detached and the proper attachments provided. It is better to use a purpose built machine such as a telehandler for this type of operation.
This loading machine has an oversize bucket but it has been made wider so that the driver can still see as the manufacturer has designed it. Compare this with the other shovel and the view from the operators position.
This bucket is on the ground but a six foot high person cannot be seen over it. It is better to fit a wider bucket or use the machine with a smaller bucket. This machine is unsuitable for the conditions it is being used in.
Another view of the same machine with an oversize bucket. Note how high the bucket is in relation to the cab, compare this with the machine fitted with the wide bucket.
This service vehicle was not fitted with side windows and reversed under the dump truck killing the driver
This service vehicle was overtaking the dump truck when they collided and the dump truck drove over it. This is a common accident where small vehicles are in the blind off side of the dump truck and either the dump truck turns right or the small vehicle cuts in, in front of the truck. The driver of the service vehicle was seriously injured.
Fitting convex mirrors and cctv will give all round visibility for the dump truck and side windows should always be fitted to utility vehicles. Traffic routes and segregation are also essential.
The convex mirror shows what field of view can be achieved around the front and down the sides of a 150 tonne truck. Combination mirrors are often fitted to loading shovels which give good all round vision.
They should be fitted in addition to normal mirrors.
They may need to be slightly in front of the vehicle to achieve a good field of view
Any mirror must be fitted so that there is no obstruction between it and the driver. These hand rails get in the way and the mirror must be moved.
Here a lifting ring is attached to the tooth of a bucket. This is unacceptable for lifting as are welded lugs inside the bucket where they may be damaged when materials are loaded. Lifting chains should also never be bent around the bucket when lifting, more reasons for not using the front end loader for lifting unless the bucket is detached.
This loading shovel was being used to adjust the cone crusher. A chain was wrapped around the crusher and the loader used to pull the chain and spin down the crusher. The brakes failed and the loader rolled forward trapping one man against the back of the crusher and the bucket. He was very seriously injured. Do not use a loading shovel for anything it was not designed for.
Visibility is also restricted around excavators. It is common for the back of the excavator to swing and trap some one against the weight. They should be fitted with appropriate visibility aids which may include cctv and convex mirrors. Note the good access on this machine.
In this case the excavator was being maintained. On completion of the maintenance the driver asked the fitter to see him back. The fitter directed the loader backwards over the land rover he had parked earlier because he could not see the back of the machine from where he stood.
This dumper has no mirrors, the lights are defective, the access step is broken and the access platform for the driver bent with missing hand rails. These are all items that get damaged easily. The truck should not be used with any of these items missing or damaged. 15% of all accidents occur when people fall from mobile plant. Lack of visibility is a factor in most vehicle accidents particularly dump truck overturns on stockpiles and tipping points, and collisions. Radar devices are often fitted either on their own or in combination with CCTV particularly on loading shovels.
Though fitted with mirrors the driver of this small dumper could not see the fitter standing behind him. The fitter did not hear the audible alarm because of the general level of noise from the bins and the truck reversed over him as he was watching the belt track. Cctv would have enabled the driver to see behind the machine and avoided the accident. The fitter is unlikely to be able to work again.
The driver of this dump truck was involved in a very common incident that can easily be avoided. He was tipping on a stockpile that is also loaded out by loading shovel. The stockpile had been loaded out at an angle to how the truck reversed and so the driver of the dump truck did not realise how close one wheel had got to the edge until it was too late. His machine did a complete somersault and landed on the quarry floor on its wheels. He was not wearing his seat belt and was seriously injured. The rules must state what the stand off distance is between the edge of the stockpile and the tipping point.
Dump trucks must approach at right angles to the tip edge. At that distance edge protection must be maintained. The stand off distance must be specified by the geotechnical specialist in the design for the tip. It will be based on the tip or stockpile height, the properties of the material tipped and the mass and design of the dump truck. Every year drivers are killed and seriously injured in similar avoidable accidents.
This dozer rolled over twice when it fell from the top of a sand face. As with all machines it must approach an open edge at right angles to it.
The driver was wearing a lap belt and complained later about the forces on his legs, and asked that a full harness belt be fitted to the machine.