Sitting properly in commercial vehicles

Transport companies are feeling the drastic consequences resulting from the problems involved in "sitting properly in commercial vehicles". Considerable costs are generated by long periods of absence for drivers, with only 5% of all professional drivers working until statutory retirement at 65.

And so the truck driver is the focus of all deliberations. The success of a company in the transport sector depends on the driver. It is the driver who is responsible for safety and adherence to schedules; it is the driver who causes and reduces costs.

And so the driver's workplace in his cab has to fulfil the basic requirement for individual adjustment of all components to suit his personal needs.

Seat position

Longitudinal adjustment of the entire seat ensures that the driver is sitting at the right distance to the pedals and other controls. This improves road safety aspects and lets the driver assume a sensible sitting posture.

Fully variable adjustment of the seat height ensures that the driver's knees are bent at the right angle with the seat at an ideal height to give the driver a clear, safe view of the vehicle surroundings, the mirrors and all the displays.

Lengthening the seat improves the distribution of sitting pressure including the thighs (distributing the weight over a larger area). There should be a gap of just a few centimetres between the front edge of the seat and the back of the knees.

Tilting the seat surface (up and back) permits sensitive adjustment of sitting pressure distribution.

Properties and adjustment of the backrest

The backrest is the central element supporting the upper part of the driver's body. The stability of the backrest and the spine-friendly shape of the backrest structure and foam components should support the spinal column in its natural shape and reduce any pressure.

The backrest tilt can be adjusted sensitively to an individual angle between the upper part of the body and hips, as well as ensuring the driver is correctly positioned between steering wheel and backrest.

A backrest with sufficient height supports the body up to shoulder height. As a rule, every truck seat has a headrest to protect the head in the event of an accident.

Adjustable side profiles in the backrest and padding hold the upper part of the body upright, fix the buttocks, permit adjustment to different anatomical requirements and offer good lateral support when driving round bends.

Separate adjustment of the upper part of the backrest allows the seat to be adapted to the individual spinal shape of the driver. The resulting contact between the upper part of the driver's back and the backrest relieves the whole neck and shoulder region, reducing fatigue and tension.

Lordosis support

An individual lordosis support allows the lower section of the spinal column to remain in its natural shape. Ideally it consists of two levels. Level 1 supports the upper iliac crest to bring the pelvis into an upright position. Level 2 is positioned above this and offers extensive support for the entire lumbar area. As an option, support can be provided by what is known as a 4-way lordosis support (front/back, up/down).

Armrests

Tilting, hinged armrests on both sides relieve the muscles in the shoulders and neck, reduce the burden on the lower spine and stabilise the posture in the upper part of the body.

Sitting climate

A balanced seat climate will enhance the driver's well-being and stamina, either as an active solution e.g. seat heating or air-conditioning, or as a passive solution with functional textiles for optimised air circulation and to allow moisture to escape.

Vibration system

A pneumatic vibration system isolates the driver from uneven road surfaces, thus protecting the spinal column and intervertebral disks from undesirable vibrations and jolts which are very harmful in the long run.

Easily accessible, intuitive, ergonomic control elements are indispensable and must comply with all currently valid safety requirements.

Driver's rest seat

Truck drivers have to observe work breaks and resting times by law, so that ergonomic aspects go further than just the driver's seat. If the driver changes seat while the vehicle is at a standstill, or if the drivers swap seats, then the passenger seat also has to fulfil the ergonomic requirements.

This "rest seat" should provide the passenger with correct support for his own specific sequence of body angles, thanks to the shape of the seat together with the structure, height, shape and fully variable adjustment of the backrest, as well as lumbar support adjustable in height and depth.

It should be possible to change the tilt of the entire seat surface without compromising the seat opening angle.

Together with a headrest that is adequately adjusted in height and an individually adjustable neck rest (which is beneficial regardless of the headrest), there is then no reason why the driver should not enjoy a recuperative nap.

There is no need to lengthen the seat: in contrast to the driver, the passenger can keep changing his sitting position during the journey in order to relieve any tension.

A good truck seat provides support in the right anatomic places. Pelvic positioning, large-scale support for the whole lumbar spine, individually adjustable seat height combined with adjustable length and tilt of the seat surface are crucial. For example, pneumatic vibration systems with electronic control offer an ideal solution that provides special protection for the spinal column and intervertebral discs, with a clear reduction in undesirable vibrations and jolts from the road surface.

Minimum requirements

• Adjustable in length
• Fully variable seat height
• Adjustable seat length
• Adjustable tilt angle of the seat surface
• Sensitive adjustment of the backrest angle
• Adjustable side profiles
• Individual, large lordosis support
• High backrest (shoulder blade height) with headrest
• Spine-friendly shape and structure of the backrest
• Easily accessible controls

Also appropriate

• Seat heating
• Passive or active air-conditioning
• Vibration/shock absorbing system
• Tilting, hinged armrests on both sides
• Belt height adjustment
• Backrest head tilt
• Compliance with additional safety requirements

None at present.

Adjusting the truck seat

An incorrect sitting posture or incorrectly adjusted seat is often the cause of backache and tension. Please therefore make sure that your driver workplace is correctly adjusted.

To do so, proceed as followings:

1. Switch on the pneumatic vibration system (if available). The system adjusts automatically to the driver's weight.
2. To adjust the correct seat height, the thighs should rest comfortably on the seat. It must be possible to floor the pedals without too much pressure between thighs and seat.
3. Ensure your buttocks are right up next to the backrest. Adjust the seat rail so that you can floor the pedals comfortably. Press your shoulders against the backrest. You must be able to reach the steering wheel with your arms slightly bent.
4. Adjust the tilt of the seat to give your thighs optimum support when you floor the pedals. When doing so, your thighs should rest on the seat without pressure.
5. Adjust the length of the seat manually so that the thighs rest on the seat up to just before the back of the knees. There should be a gap of 2 to 3 fingers width between the back of your knees and the edge of the seat.
6. It must be possible to adjust the height and depth of the lordosis support with full-surface contact in the lumbar area without having to apply any additional pressure.
7. The adjusted side profiles may not constrict the upper part of your body.
8. If present, use your armrests for noticeable relief of any tension in your shoulder/neck muscles.

Remarks

Even if your truck has the very best seats, it is still vital that you stop regularly for some exercise. Traffic congestion is half as tedious if you interrupt the boredom with some exercises in between. This can help you relax! It is a well-known fact that sleep is the most important regeneration phase for body and mind. It is therefore crucial to offer the stressed professional driver a bed system in his berth that is even better than most household beds.

There are two winners when it comes to well-conceived, ergonomic driver's cabs with exemplary implementation of all these points. The main winner is the truck driver, who gains from the various elements that help to preserve his health and quality of life while also enhancing his level of job satisfaction. The second winner is the employer who will see financial gain from investing in his human resources. Such investment reduces sick leave levels, improves safety and also ensures employees are motivated!

But both truck driver and employer can only benefit in the long run by remaining well informed and suitably trained. A technical sales consultant is a service provider who also provides problem solutions. Specialist know-how needs to be acquired and extended to show the right level of expertise for gaining confidence and credibility. Technical sales consultants need to be familiar with basic anatomy and know what the driver has to take into consideration when sitting in the truck. The technical sales consultant should also know which criteria must be fulfilled by an ergonomically well-designed seat. Only then can he provide expert advice in this field.

In-depth information and training courses on these subjects are indispensable for the technical sales consultant and service provider serving the haulage industry. You should therefore not hesitate to ask your consultant or service provider about their level of know-how. Qualified advice is very much in the interest of your personal health.

To summarise, it should be said that a fleet of trucks equipped with back-friendly driver's seats and ergonomically correct regeneration areas, such as the rest seat and bed, make an appropriate contribution to sustaining the health of the truck driver.