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Four Wheel Drive Safety.
Four wheel drive safety
became an issue when the descendant of the little Suzuki LJ20
started to be sold as a fun-machine rather than as a farmer's work-horse.
It could fall over if driven round corners too quickly.
The Samurai promptly got a wider track to fix the problem
and the later Vitara is lower and wider still.
Have you noticed the lengthening of axles and the blossoming of wheel-arch
flares on new model Mitsubishis, Nissans, Rovers and Toyotas since then?
Makers of 2WD cars, irritated by the success of SUVs, grumbled about the
latters' avoidance of crash-safety regulations as applied to passenger cars.
4WD makers had their arms twisted and new 4WDs comply with coming regulations
covering front and side impact. Air-bags are often fitted!
Incidentally, new regulations do not require air-bags.
They do set standards of survivability in crashes and
fitting air-bags is one way highly marketable way to meet the standards.
(Personally, I have always felt that road-safety would be improved if
all driver safety devices were removed.
If the driver sat somewhere up front on the bonnet (hood), unprotected
except by a nice comfortable arm chair, the resultant feeling of vulnerability
should moderate behaviour nicely. The scheme does have one or two practical
disadvantages and probably won't catch on.)
The New Car Assessment Program (NCAP) tested the
Land-Rover Discovery, Mitsubishi Pajero, Nissan Patrol,
Suzuki Vitara and Toyota Land-Cruiser, between October 1993 and June 1994,
in frontal (56kph) and offset-frontal (60kph) impacts.
NCAP is a research body funded by motoring and insurance organizations.
The frontal tests are into an "immovable object" and correspond
roughly to hitting a stout wall or tree,
or to hitting an identical vehicle head-on.
(The heavier vehicle generally has a considerable advantage
in an accident with a lighter vehicle.)
The offset tests are into a crushable pad made of aluminium.
All 4WDs performed acceptably.
The Land-Cruiser occupants had least chance of a life-threatening injury:
31% for the driver and 13% for the passenger.
Drivers face less chance of a serious injury in models fitted with air-bags.
Nissan and Suzuki passengers had the highest risk of serious
injury: 63% and 65% respectively.
NCAP tests have come in for some industry criticism because they
are carried out at a higher speed than that used by licencing authorities,
but this just sounds like self-interested griping.
(ADR 69 applies to new models introduced into Australia after July 1995
and to all vehicles manufactured after 1 January 1996.
It involves a frontal impact at 48kph (30mph), passing set criteria.)
Bull-bars (roo-bars, brush-bars, park-by-feel-bars, ...)
are also being questioned for two reasons.
One is the risk to pedestrians from bars fitted to 2WDs or 4WDs.
The other is the worry that a bull-bar might,
by changing the characteristics of the front bodywork,
confuse the sensors that trigger the air-bag at just the right moment.
The air-bag inflates and then deflates quickly;
a few milli-seconds too early or too late could be fatal.
There is a rush of research activity to check the effects
of current bull-bars and to design acceptable ones.
The current guide on bull-bars from the Vehicle Safety Branch
of Vic Roads states:
... if the vehicle is fitted with an air bag or is a vehicle
required to comply with Australian Design Rule (ADR) 69 -
Full Frontal Impact Occupant Protection, then the bull bar must be:-
- one certified by the vehicle manufacturer as suitable
for that vehicle; or
- one which has been demonstrated by the bull bar manufacturer to not
adversely affect compliance with ADR 69 or interfere with the
critical air bag timing mechanism as the case may be.
Demonstration of compliance with ADR 69 requires full scale barrier testing
and to demonstrate that the critical air bag timing mechanism is not affected
when a bull bar is fitted also requires full scale barrier testing.
The 4WD roll-over issue surfaced again in 1994/95, aimed this time
not at the lowly Suzuki but at the lofty Range Rover.
Following a small number of tragic accidents some sensational
newspaper articles were written.
The Daily (Electronic) Telegraph (ET) interviewed British police drivers,
who use Range Rovers for motorway (freeway) patrol
and came up with a more balanced view.
Sanity prevailed. 4WDs are not sports cars.
They tend to be tall, for good ground-clearance, with a high centre of gravity.
Land-Rover used to tilt-test their vehicles beyond 45 degrees (do they still?).
That should guarantee against a cornering roll-over on a flat road in principle
(coefficient of friction less than 1.0), but
loading, slope and dynamic effects can remove any margin of safety.
Driven appropriately, 4WDs are extremely safe and there are many
cases in which a 4WD driver avoids an accident, or walks away from an accident,
that would have killed a 2WD driver. They do not get counted.
Some awful 4WD advertising campaigns are also at fault.
If an apparently standard 4WD is shown on television leaping over sand-dunes,
an inexperienced driver may be encouraged to try the same thing
perhaps with fatal results.
A racing 4x4 bears about as much relation to a show-room model
as a formula-one car does to a shopping cart.
Surely such campaigns are not run in litigious America?
It is nice to see the Australian advertising industry making an award
for the responsible advertising of 4WDs in 1995 (to Rover).
Further Reading and References:
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