With a typical car emitting about 4.7 metric tonnes of carbon dioxide every year, and more than 1.2 billion vehicles on the world's roads right now, it's safe to say we have way too many cars contributing unsustainable levels of greenhouse gases to Earth's atmosphere.

But it's a luxury we've had for decades, and for many, it won't be an easy thing to give up, even in exchange for safer and more environmentally friendly options such as driverless cars. So governments around the world are looking to replace one luxury with an even better one: cash.

After Milan - the second most populous city in Italy - experienced 30 straight days of unhealthy levels of smog last December, the government put a temporary ban on cars in the city centre, and cut public transport ticket prices to encourage the public to ditch their personal vehicles. 

Two months earlier, Norway announced it was permanently banning cars from its capital's centre, and Paris banned cars from its CBD for 24 hours to give its citizens a rest from the "noise, pollution, and stress". 

But in an effort to find a solution that will stick in the long-run, officials in Milan have acknowledged that greater incentives are needed, and are planning on paying commuters who choose to ditch their car and ride a bike instead.

"We want to focus the public opinion on the fact that moving by bike is much healthier for them and for the city," Pierfrancesco Maran, Milan's mobility councillor, told the press.

It's not yet clear exactly how this would work, but it could be that the government would set up a 'reverse-toll' system for bike-riders, or they might be reimbursed on a regular basis depending on how many kilometres they ride.

Milan officials are currently looking at a French experiment conducted in 2014 that reimbursed bike riders, and programs in Belgium, the Netherlands, and the UK that paid commuters to cycle at rates equivalent to about 30 cents a mile (1.6 km), tax-free, Adele Peters explains at Fast Company.

"Under the French system trialled in 2014, employees were paid 25 cents per kilometre they pedalled to work," Rosie Scammell reports for The Guardian. "A pilot on the same principle is currently being rolled out in Massarosa, a small Tuscan town, where 50 people are said to be taking part. With the numbers in Milan likely to be considerably higher, Maran's office has suggested using an app to keep track of people cycling to work."

While it sounds like an awesome plan, with lots of 'win-wins' everywhere, it might not be that easy. "In the French experiment, out of more than 8,000 employees who participated, only around 400 actually switched to a bike," says Fast Company. "Milan - with some of the worst traffic in Europe - is a city addicted to cars."

Eleonora Perotto, the mobility manager of Milan's Polytechnic University, has been asked to advise Maran and his office on practical solutions to the paid cycling scheme, and told The Guardian that money (especially the very small amounts that have been offered in previous programs) is not enough. Cities need to also make cycling easier, safer, and more convenient to get the plan to work.

Ralph Buehler, an associate professor in urban affairs and planning at Virginia Tech, agrees: "Experience shows that you can make it more difficult for people to drive, but it's politically easier if you have other options: good incentives to cycle, good public transport, easy to walk."

To its credit, Milan is showing that it's serious about wanting things to change, and over the past few years, has added 50 percent more bike lanes, and doubled the amount of bike-share stations - something that Beijing is also working on to combat its own pollution woes. 

Milan's also introduced a 'congestion charge', which has actually seen 20 percent more people using public transport since it was introduced four years ago. 

With Norway recently committing US$1 billion to build dedicated bike highways, and Denmark installing traffic lights that give priority to bikes and buses, the writing is on the wall for personal car ownership. We've had our fun, but enough's enough, and now governments around the world just need to figure out the best way to ween us off this very bad habit.