The days of passive aggressive notes left on the windshields of illegally parked cars may be coming to an end. That's thanks to a new app that utilizes the power of the crowd to flag bad drivers for local traffic cops, bringing the offensive curb-huggers public shame and, hopefully, a whopping traffic ticket.

The TowIt app, created by Michael McArthur and Gregory Meloche, launched in Toronto and is being used sparingly in other cities (in New York, someone has kindly flagged an NYPD van for towing). Users snap a photo of the offending vehicle and upload it to the app, where it will appear on a map for everyone to see and share. It's a fun idea. But can it be an effective tool for putting an end to parking problems?

Shame is a powerful feeling. According to one study, this guilt-inducing emotion "is an important motivator of a desire to change oneself for the better." That said, TowIt and apps like it will only work if they're ubiquitous. Right now, if you post a photo to TowIt, it's unlikely many people, let alone the offending driver, will see it or feel any shame at all. In this case, there is only power in numbers, and TowIt needs to get its numbers up to have any use at all. McArthur says, "We have hundreds of interested people already," but it will take more than that to be an effective shaming tool. Right now, the app is "basically a geotagged map of lousy parking jobs," says Lamar Anderson at Curbed.

Of course, the app could also skip the shaming and go directly to the punishing by connecting with law enforcement and actually getting people towed. And this is the ultimate goal. McArthur and Meloche have already met with the mayor's office and traffic services of Toronto. They eventually want the app to be smart enough to know the parking laws across a particular city and automatically identify an illegally parked car and remotely alert traffic cops, who would write the ticket and call the tow truck then and there. The app would identify repeat offenders, those especially inconsiderate people who are constantly parking in the bike lane or in front of a fire hydrant, and hopefully break them of their bad behavior. "I am offering the police a free solution, with no cost to them and no cost to the taxpayers, that is just going to make them more efficient, which in turn will save them or make them more money," McArthur says.

But can we trust an app to do the job of a traffic cop? Parking tickets handed out by actual human officers get challenged all the time (there's an app for that). You can imagine the uproar when someone finds out their ticket was administered by a digital tool. "There are many exceptions in the parking bylaws that officers are trained to interpret what is and what is not permitted," says Constable Clinton Stibbe, media officer for Toronto Traffic Services. "We have to look at everything."

The creators of the TowIt app insist they're not just trying antagonize people. "We're not out here to ruin people's lives or tow people endlessly," McArthur says. The app will eventually help prevent tickets entirely by telling users if they're allowed to park in a particular spot, and for how long. No more wandering the block for a sign that's barely interpretable or failing to see a faded yellow line painted on the curb. Just open the app and know if you're good to go. "I could push a button in the app that says I'm leaving my car here now, ping me 10 minutes before the tow route is going to take place, so I have a reminder to move my car," McArthur told Co.Exist.

If you want to give TowIt a try, it is available for iOS and Android, and is coming soon to Windows and Blackberry.