[associates] Backup Steering
- From: "Carol and Norm Simoes" <carolnnorm@xxxxxxxxxxx>
- To: <associates@xxxxxxxxxxxxx>
- Date: Fri, 01 May 2009 15:46:57 -0700
Hi All,
I have been retired from the job of Rehabilitation Engineer for the
California Department of Rehabilitation since 2006, but this had become an
issue while I was working. Several of the vehicle modifiers had mentioned
the improved reliability of the reduced effort steering systems and the
belts which normally provided their power and questioned the need for backup
systems. I agree, however, with Mr. Bradly that the cost of any failure
could be very high. We all know the reason for reduced effort and zero
effort steering (yes, I too am still old school) is the presumption that the
driver with a disability could not, in the opinion of the evaluator, safely
steer the vehicle without such an assist. It seems to stand to reason
therefore that reduced effort steering, at whatever level, is a necessity
for drivers with significantly diminished upper extremity strength. But is
it needed by all of them? I have definitely known that an able bodied driver
can operate a car with a defective power steering unit. One of our younger
driving instructors back in the mid '80s drove his car from the Los Angeles
CA vicinity to Phoenix AZ and back on the weekend to visit his girlfriend.
His power steering had gone out near the end of the week and he had a
choice. Fix it or not see his girlfriend that weekend. I cannot vouch for
how safe he was but he made it there and back. The point is, however, that
no one has really researched/published the force at the wheel rim needed to
turn the steering wheel when the power steering is out and the vehicle is
moving. (Obviously, it is much more difficult to turn the wheel when the
vehicle is sitting still, but then not much bad happens at that speed).
Instead if just making a decision that back up steering systems are
expensive and pose their own safety hazards, perhaps it is time to determine
just how much strength is needed to get the vehicle to the side of the road
(or negotiate a slight bend in the road) if the belt breaks when a vehicle
is traveling at 60 mph. Or how much strength is needed to turn the wheel
enough to follow an off ramp at 35 mph if the belt breaks.
The loss of steering fluid from a leak is a different story and that is the
reason for the extra fluid reservoir which normally comes with a backup
system. The total loss of fluid may only be preceded by some signs of
"steam" and smell from the engine compartment for the alert driver, followed
by the onset of the backup steering pump. Unfortunately many drivers may
not notice the earlier signs or even the "whine" of the backup pump (or even
the meaning of that seldom seen lamp on their control panel), so when all
the fluid is gone, they will have no power steering, with or without an
installed backup system. They may also run the risk of fire which, without
quick action could disable the power needed to operate the lift and door
openers.
I would like to see information available to evaluators on how much strength
is actually needed to control a moving vehicle without reduced effort
steering and information available to evaluators about warnings to be given
to drivers with disabilities about first signs of power/reduced effort
steering failure and what to do immediately. I am not sure whether these
are projects best pursued by NMEDA or ADED, but both should be involved
since both organizations are stakeholders in the safety of the drivers.
Norm Simoes
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