Snake oil that's supported solely by the punters' 'testmonials', in
the complete absence of any relevant scientific evidence whatsoever.

Why would the roo (or anything else) hear the device above the vehicle
noise, and why would it react any differently to either sound?  In any
case their usual reaction to any strange sound is to bolt in whatever
direction takes their fancy... which may or may not be into the side
of your car (or in front of it).

Here's a couple of testimonials of my own (take 'em for what they're
worth).

1)  Had a couple of wind operated animal scarers on the front of the
ute for years (got 'em off the $1 specials table at a parts supplier).
Roos and domestic livestock took no notice whatsoever (beyond their
normal reaction to an approaching vehicle or one driving alongside
them).

2)  Bloke I know fitted one of the well known brand electronic devices
to his ute (at great expense) and collected a roo on the first night
out.  Complained to the manufacturer who told him the roo musta been
deaf.

I reckon they all are (when it comes to secret ultrasonic messages
that are supposed to tell 'em to run in the other direction).

The only way to avoid hitting any animal is to drive slow enough to
give it a chance to get out of the way.  The better educated ones will
often stand and watch you pass by (if you don't scare the sh.t out of
'em first).  ;-)

Sounds like you've got a good test bed for a whistle there.

I had them fitted to my Hilux, but as John H says, there's no
scientific proof that they work. I didn't hit anything during that
time but even before I had the whistles there were times when I would
go for months without seeing/hitting anything.

One thing I will say though, a good air horn (as fitted to my ute)
does make the roos get the hell away from you - not just scatter in a
confused mess.

You'd have more effect sticking a mic in your shorts and dropping a blurter.

Jason

It's all bullshit designed to empty your wallet and give you a false sense
of safety.

A scientific evaluation of the device concluded -

"The promotional literature proclaiming the scientifically proven efficacy
of thisultrasonic deterrence device, the Shu Roo, grossly exaggerates its
capabilities. The results of the signal characteristics and behavioural
responses generate four clear conclusions:
· The Shu Roo is not purely ultrasonic.
· The Shu Roo does not produce sound that is detectable at 400 m.
· The Shu Roo does not alter the behaviour of either eastern grey kangaroos
or red kangaroos.
· The Shu Roo does not reduce the number of collisions between vehicles and
kangaroos."

http://www.browsingdamage.org.au/bender2001.pdf

Air horn time

-mark

Fit the most appropriate form of bullbar available for the vehicle,
and don't bother hanging crap off it.  I'm quite happy with the
"Team Poly" "Smartbar" on my Falcon but I haven't hit anything
bigger than a crow so far...  The crow strike was totally
undetectable after the event, which is more than could be expected
for the same vehicle without the bar.

just buy a truck and fit a f.cking big steel(not alloy) bullbar
then cruise along and ignore the thumps and bumps

Kev

you fit one
if you don't hit a roo
then it obviously works
if you do hit a roo
well it doesn't work and you can go get your $3.99 back from supacheap
where ya bought it

Kev