Someone fetch a shovel--this is one cash-cow complaint that's as good as dead.

It's a painful truth to expose, but it seems photo radar, the money-making, ticket-generating speed contraption so beloved by the Calgary Police Service, actually works.

That's right. Loathe it as you may, a University of Calgary study shows photo radar really does prevent collisions.

Worse yet, the number of crashes falls in proportion to the number of cameras used and the severity of the fine: More tickets, safer streets.

Photo radar makes millions, but it saves lives, which buries the cash-cow argument for good. Damn.

Calgary's police have always claimed as much -- and now they have the scientific evidence to support the purchase of additional photo radar equipment, because it keeps our streets safe.

With city hall budget debates a month away, aldermen say the study could sway the case for more cameras.

"This certainly reinforces what the cops have been saying for a long time," said Ald. Diane Colley-Urquhart, who sits on the Police Commission.

"It is always better when someone else says it and it doesn't appear self-serving. I'm pleased -- just in time for budget."

Trust a Calgary scientist to do something annoyingly useful, just as lab-coated colleagues around the world are being mocked with Ig Nobel prizes, a satirical award for pointless research.

There was a 2008 Ig Nobel given for "A Comparison of Jump Performances of the Dog Flea and the Cat Flea," and another for "The Spermicidal Potency of Coca-Cola and Pepsi-Cola."

If only Dr. Richard Tay, road safety chair of the University of Calgary's Schulich School of Engineering, had an interest in soda pop and fleas.

Instead, Tay is preparing to publish two studies on police traffic strategy, both with real-life impact on local motorists.

"Photo radar as a cash cow is just a public perception," said Tay.

"People learn over time -- they get a few tickets, and they learn to reduce speed and change their behaviour."

The first paper, presented earlier this year at a U.S. Transportation Research Board meeting, is entitled Optimizing Photo Radar Enforcement: Do We Have to Catch Offenders to Reduce Crashes?

As it turns out, the answer is yes -- Tay's study, based on Edmonton statistics, shows the mere presence of photo radar doesn't dramatically reduce crashes, but fines do.

"This study found both the number of speed camera operating hours per month and the number of drivers apprehended per month has statistically significant effects in reducing the number of injury crashes per month," reads the conclusion.

Tay says warnings do little to deter speeders.

"If there is a fine, they're are going to remember that more than a warning," said Tay.

The second study, The Effectiveness of Automated and Manned Traffic Enforcement, is set for publication in the International Journal of Sustainable Transport.

It's a comparison between photo radar and old-fashioned traffic cops.

Photo radar might soothe traffic in general, but Tay's second study shows real police officers are still the best cure for lead-footed drivers.

"We found that while manned enforcement has a significant impact on both total and serious crashes, automated enforcement only has an effect on total crashes," states the report, based on data from Queensland, Aust.

Tay said the difference is real police leave a lasting impression on hardcore speeders, which the study shows to be mainly young men, aged 20 to 29.

According to the study, manned enforcement deters high-risk drivers, while photo radar provides a deterrence for the general traffic flow.

"For a small group of drivers, photo radar is never going to work," said Tay.

He credits live police with providing an instant crime-and-punishment deterrent that seems essential for stopping severe speeders -- if caught by a manned radar trap, there is an instant ticket and safety lecture engrained in the offender's memory.