The world’s leading truck manufacturers spend large portions of their budgets on research and development to build safer truck cabs. While safety critical items like brakes and tyres are central to a truck’s safety profile, the cab is the ‘home-away-fromhome’ for drivers and assistants and today’s premium truck models are more comfortable and safer than most luxury cars. Paul Collings reports.

With driver fatigue playing such a prominent role in truck accidents, it has become increasingly clear to truck designers that cabs need to be both ergonomic and strong to protect occupants as much as possible in the event of an accident and generally, to make the task of driving less physically demanding. 

In recent years, a host of new truck safety technologies have been introduced to models from Europe, the Americas and Asia. FleetWatch has devoted much coverage to these innovations, many of which are found on truck tractors currently operating in South Africa. 

Volvo Trucks subjects its cabs to the most stringent of crash-tests to help the ongoing improvements in safety technology.

Active and passive 
The approaches to enhancing truck safety adopted by the likes of Mercedes-Benz, Volvo and Scania are defined along the lines of those safety features known as ‘active’ and ‘passive’. Truck buyers concerned about the longevity of their drivers should ask truck sales people what safety features each model has and whether they come as standard fitments. 

Basically, ‘active’ safety features work to help truck and driver avoid accidents, be they rollovers, jacknifing or collisions with other road users. These include advanced electronic braking systems like Active Brake Assist (as found on the latest Actros), Electronic Stability Programme (common on both light and heavy trucks), proximity control that governs following distances, and early warning systems like lane monitors which emit a harsh buzzalarm should the truck cross the barrier lines on the road.

The 'passive’ safety element of truck design is concerned with limiting the effects of accidents through various technologies including stronger cab construction and ensuring the driver doesn't leave his seat during impact by fitting the best seats and belts. 

Brain box 
The research and development process behind cab design and construction is a scientific quest that goes beyond mechanical engineering to include a number of other disciplines like human behavioural studies and accident investigation. Volvo Trucks has a long and proud history of safety innovation and according to its brochure material: 

“The human factor contributes to about 90% of all traffic accidents. The traffic environment contributes to 30% of accidents and vehicle defects to about 10%. In other words, an accident can be due to more than one factor.” 

An Accident Research Team conducts intensive safety testing in the Volvo laboratories to better understand the factors behind actual accidents to further reduce their frequency. 

Part of this process is a project called HMI (Human-Machine Interface), which strives for the optimum arrangement of controls, instruments and pushbuttons in the vehicle. 

Research into driver behaviour is even more important, states Volvo Trucks, and researchers are working on improved driver training, as well as on the development of an ‘eyetracking’ system, where in-cab cameras are used to study the driver’s eye movements and trigger an alarm should the driver succumb to fatigue. 

Crash testing 
Modern cab design is based on the principle of transferring the kinetic energy of the collision through the sub-structure of the cab, be it chassis beams, cab frames or via the use of bearings and special mountings under the cab that allow the cab to shift backwards on impact thereby dissipating the kinetic energy and reducing danger to cab occupants. MAN’s TGL range uses such technology in its ‘Safety Cell’ cabs. 

Scania (and Volvo Trucks) have to conform to Swedish cab safety standards, which are the world’s strictest on structural cab strength, states Scania: “Impact testing includes a frontal crash into a concrete barrier at 40 km/h and trailerback crashes at 35 km/h. Underrun protection is now incorporated into the design of the front bumper, which also performs the role of a spoiler to improve aerodynamic characteristics. Testing of the new system involved creating an offset crash between an Audi A3 passenger car and a Scania truck at a collision speed of 60 km/h. This type of impact (involving 75% of the car’s frontal area) was demonstrated to be survivable without serious injury; car occupants would have been able to get out of the car unaided. The truck driver would have maintained control of the truck. Such conditions following an impact of this type indicate high safety standards of both the car and truck.” 

Safer humans - Subjecting crash-test dummies to collisions at various speeds helps truck designers develop safer seats, seat belts, airbags and windscreens.

In the detail 
The obvious best thing to come from truck safety R&D is a dramatic drop in accident numbers and casualties. Using as many ‘active’ and ‘passive’ safety features on a truck as possible does assist the process. Our local drivers need a bit of help out there in this regard and should that rig get sideways, technology like knee-protection beams, a kinetic energy-absorbing steering column, integrated seat belts that adjust to the driver’s height for better comfort and protection, airbags and a glued-in windscreen for extra cab strength could just be the thing that saves the day.