12 April 1996

Safety work is aimed at ATV roll-over protection

By Andy Collings

ROLL-OVER protection structures – ROPS – could soon be a feature on ATVs.

Recent research by the Health and Safety Laboratory has been assessing the feasibility of ROPS in terms of ergonomic, dynamic and mechanical considerations.

Health and Safety Executive figures reveal that over 50% of all ATV accidents investigated are the result of machines rolling over sidewards. This compares with about 5% of accidents through tipping forwards and 7% rearwards.

It follows then, that the main thrust of research is to find a way of reducing the number of injuries – and deaths – caused by lateral overturns.

In an ideal world an ATV ROPS system would provide a safe volume for containment of the operator – the volume of space under an overturned machine on a flat surface into which the rider would be pressed.

But current ATV designs do not lend themselves to having a cab, roll cage or any front-mounted ROPS.

Normal postures

Chief researcher, David Allinson, points out that normal riding postures extend above the operators seated position and beyond the rider in front of the handlebars.

"This makes it impractical to fit ROPS either above or in front of the operator," he says. "We concluded that the most obvious and workable protection was to fit either a single pole or a roll bar at the rear of the machine to prevent an ATV rolling more than 90í. "

But where can a roll bar be attached to? "Carrying frames are not strong enough," says Mr Allinson. "And ATV frames are generally narrow and lightweight with no provision for additional structural attachment. Most ATVs, however, do have suitable attachment points if they are looked for – foot pedals or engine mounting frames, for example, but they may need reinforcing."

Tests to assess the forces involved when an ATV rolls over indicate that a pole with a 20cm (8in) diameter and 16mm (0.6in) wall thickness was required.

But Mr Allinson believes these dimensions make it impractical to fit a single pole and, furthermore, a roll bar capable of absorbing the energy in an overturn would also result in extensive machine damage.

"Further work is required to take the ATVs frame stiffness into account. Energy absorbing mounting points may be the answer."

With an alarming number of ATV accidents continuing to occur each year – a number which is unlikely to reduce, despite the HSEs best efforts – it would clearly make sense for ATV operators to be protected. After all, tractors have to be fitted with ROPS.

For those who wish to see just what Mr Allinson has achieved to date an ATV fitted with a roll bar will be on display at most of the big agricultural shows this year.

Importers view

"We would welcome any system which would make ATVs safer for operators," says Stuart Parker, safety officer for Polaris importer, EP Barrus.

A predictable company line echoed by several other ATV makers. But when it comes to the actual fitting and styling of, say, a roll bar, the picture is not quite so clear.

Mr Parker believes any developments should be integrated into the original design of the vehicle.

"Current ATV designs do not lend themselves to such adaptations," he says. "It would be wrong for anyone to try to fit roll bars on to existing machines. If they failed they could cause more injury than if they had never been there."

Roll-over protection for this rider may be too late. The use of protective headgear may also have been a good idea.