A folded sheet of plain white paper appears to be all it takes to fend off Toronto police parking enforcement officers on a busy downtown street that runs through the University of Toronto.

It's happening on Sussex Avenue, a narrow, busy road lined with century-old homes near Spadina Road and Bloor Street West, where most residents need to display permits to park their cars on the street.

And now, Toronto police are looking into which parking enforcement officers might have been involved in the alleged scheme to exempt campus police officers from paying parking fines on Sussex.

There are also several U of T buildings, including the John P. Robarts Research Library. Students and others lucky enough to find a parking spot on Sussex are limited to one-hour parking. Unless, it appears, you place a neatly folded piece of white paper on your dashboard.

"I don't think it's fair," Abel Cartaya told CBC News after he parked his car on Sussex Avenue this week to visit the university.

"They have two sets of rules, but there should be only one," he added.

Cars traced to U of T security

Over three days, CBC News observed numerous cars parked on a stretch of Sussex Avenue for at least eight hours that were not ticketed for violating parking restrictions.

Some were parked there daily.

University of Toronto campus police officers routinely park their personal vehicles outside their police station on Sussex Avenue with a white, folded piece of paper in the dash. (CBC)

In each case, the vehicles had a plain, folded sheet of paper on their dashboard, and were parked on Sussex near the university's campus police station.

CBC News traced the owners of the vehicles through publicly available Ontario Ministry of Transportation data. The vehicles belong to University of Toronto campus police constables, sergeants and staff sergeants.

Some make well over $100 000 a year, according to the province's Sunshine List. Their vehicles included Mercedes Benz sedans, Audis and BMW SUVs.

Toronto Police parking enforcement officers have the authority to decide who gets tagged, and who doesn't, on public streets.

CBC News observed those officers patrolling Sussex Avenue several times a day. They slapped many vehicles with $30 tickets. However, none belonged to campus police officers with a white sheet of paper on the dashboard.

Toronto police investigating

Brian Moniz, operations supervisor for Toronto Police Parking Enforcement Operations, says they're now investigating the situation and trying to identify the police employees involved in the alleged scheme.

"We're here to maintain the public's trust and by overlooking, or not ticketing certain vehicles, or those that belong to people in our industry, it's not to our expectations," he told CBC News.

Moniz also insists Toronto police would never make a deal with campus police to violate Toronto's parking rules with impunity.

"I can tell you this was never done on a corporate level, nor would we ever sanction it. Again, it's something we're going to have to look into and see how this started," he said.

Brian Moniz, operations supervisor Toronto Police Parking Enforcement Operations, says an investigation is being launched into allegations parking officers are giving preferential treatment to some people. (John Lancaster/CBC News)

U of T says it is not aware of any of its campus officers getting preferential treatment.

"The university is not aware of any special arrangements with the City of Toronto regarding parking and actively supports the city enforcing parking regulations near our campus," a brief email from the university's media relations department reads.

Second alleged parking scheme

This isn't the first time Toronto police parking enforcement officers and campus police have seemingly hatched a plan to avoid fines for breaking parking rules.

In 2016, both police and university officials vowed to crack down after CBC News revealed campus police officers were avoiding parking fines.

At the time, some would put a campus police uniform patch on the dashboards of their personal vehicles while they worked. The patch was meant to tip off parking officials that the vehicles shouldn't be ticketed.

Local residents caught on and so did some university students.

Some even purchased their own campus police patches on eBay for as little as $1.00 in an effort to avoid parking fines too.

Campus police stopped doing it shortly after the scheme was exposed.