Jack-knifing in icy weather

Severe weather has caused a number of trucks to jack-knife. The Road Haulage Association today reminds industry of the need for extra vigilance in the loading and driving of trucks, as they continue to provide an essential service to business and the public.

1. Jack-knifing is caused by loss of traction, when the trailer tries to overtake the tractor unit and the driver loses control of the truck, as the front slews to one side. The rear of the truck is pushed forward.

2. Jack-knifing is much less of a problem now than it was in the past, due to technical improvements. It mostly occurs in extreme conditions.

3. Inappropriate loading can lead to jack-knifing in extreme conditions. If the load is concentrated towards the rear of the trailer, it reduces the weight on the drive axle and therefore the driver’s control, especially when going downhill or braking.

4. There may be a training issue, especially for some older drivers who learnt before the introduction of ABS and EBS braking systems. Such drivers may still be “pumping” the brakes, rather than keeping a constant pressure on the brakes. However, drivers should not be relying on their ABS in the first place – they should be planning ahead and driving more slowly.

5. Drivers should ensure that their ABS and EBS is working satisfactorily. A build-up of snow and ice on the sensors could affect performance and that would show on a warning light. Older vehicles may not have these electronic safety aids, and extra care must be taken where that is the case.

6. Companies and their drivers should encourage appropriate loading.

7. Drivers should proceed with especial care during snowy and icy conditions and leave considerably more room between themselves and the vehicle in front. Stopping distances can be up to four times greater.

8. Lack of gritting makes roads more prone to jack-knifing.