Doubt cast on speed readings
From The West Australian
By Gareth Parker
May 09, 2006
Up to one in eight speed camera readings
could be inaccurate because of weather conditions such as rain or
wind, a leading automotive engineer claimed yesterday.
South Australian-based Grad Zivkovic said radar and
laser technology used by WA police were susceptible to “ghost
readings”, which could affect accuracy by up to 30 per cent.
Police have rejected the claims.
He told Today Tonight, in a program to be broadcast
on Channel 7 at 6.30 tonight, that speed camera user manuals warned
about the possibility of ghost readings.
But Australian police departments, including WA’s,
refuse to release their manuals to the public, citing commercial confidentiality
clauses in contracts with manufacturers.
Mr Zivkovic, who conducts crash testing for car manufacturers,
said car companies refused to accept that readings from radar or laser
speed cameras were accurate for the purposes of crash testing and
they would not reply on them.
His doubts about the accuracy of speed cameras surfaced
when he bought a Stalker II hand-held radar, which uses technology
similar to WA police speed cameras, as a back-up system for his crash
testing.
During testing, he crashes cars at 48kmh, measured
by at least two independent photographic systems. He was stunned when
the radar occasionally threw up readings as high as 150kmh.
“I was under the impression they were very accurate
and they very rarely made mistakes, Mr Zivkovic said.
“Since I got mine and used it for four or five
years I discovered about 10 to 15 per cent of readings are inaccurate.”
He said extreme weather could cause inaccuracies.
Water splashing from wet roads, tree branches blowing in the wind
and dust could all interfere with a radar or laser beam, affecting
reliability. Readings could also be affected if radar or laser beams
bounced off metal objects like garage doors, road signs or other passing
vehicles.
In one South Australian case, a motorist received
a traffic infringement notice alleging his parked car was travelling
at 65kmh.
Police spokesman Sgt Graham Clifford immediately rejected
Mr Zivkovic’s findings.
“He is entitled to his opinion, but our cameras
are tested over and over again,” he said. “Our people
want to get on and make the road safe.”
The WA Police policy manual,
released to The West Australian warns “heavy rain and blowing
dust can cause a scattering effect which may reduce the effective
range of radar devices”.
