Toronto isn’t the first city to consider demolishing an urban highway.

As Toronto ponders the future of the Gardiner Expressway, attention turns to other cities that have already made the decision to destroy the downtown highways.

North America in cities like San Francisco, Boston, Portland, and Milwaukee have torn down at least one freeway within the last 30 years.

Most North American urban highways were built in the 1950s and 60s. They were promoted as boons to urban economic development after the rise of suburban living. Freeways literally paved the way for suburbanites to easily commute back to the city for work and leisure.

But today many have reached the limit of their useful lives, and these structures are now falling apart. When their expensive ongoing maintenance hits home, a conversation about removal often begins.

Here are the most recent positions from Toronto politicians about demolishing the Gardiner, along with observations of what happened in other cities.

"The Gardiner is very useful and if we tear it down it will be traffic chaos for five or six years. I do not want to see that." — Mayor Rob Ford.

Before tearing down the San Francisco Embarcadero Freeway, damaged by an earthquake in 1989, traffic nightmares were widely predicted. But as it turned out, improvements to surface streets, transit and the walking environment helped soak up a good share of the former highway traffic.

"There is an assumption that all current traffic will have to be diverted when you tear down a highway," according to Chris McCahill, senior associate at the State Smart Transportation Initiative at the University of Wisconsin. "But that’s not what happens. Instead, people change their behaviour drastically — they change what time they travel and where they go."

Many peak-period freeway travellers don’t need to be on the road at all at that time of day. "But several conditions need to be met to ensure the success of a highway demolition," McCahill said. One is increased investment in transit.

What replaces the freeway is also important. A surface boulevard, even if fairly large — like the one proposed for the Gardiner — needs to integrate itself well into the existing street network.

"Is there some crumbling? Absolutely there is. It is an old bridge that needs some work, but we can clean it up and beautify it." — Rob Ford

There are few, if any, successful examples of a beautified freeway, especially in an urban context, said McCahill. "There is a growing perception these do not belong in a city, that they aren’t beneficial for the city in any way," he added.

"Tearing down the Gardiner will only add to the cost of gridlock." — Deputy Mayor Norm Kelly

Gridlock costs are usually calculated by assigning every hour a value and then tallying up the total hours a city population spends commuting.

But that is not meaningful, said Bill Holloway, a transportation policy analyst also at State Smart Transportation. An extra 10 to 15 minutes spent by an individual on a commute has no noticeable effect on their lives.

The conclusion that "movement of goods" or truck traffic will be badly hurt by removing the Gardiner is also "probably overblown," said Holloway. A lot of city roadways have significant free capacity at night so trucks can shift to other routes or off-peak hours.

"The freight industry will likely adjust to this pretty well," he said.

Councillor Mike Layton argued, “It would probably increase the value of real estate around that section and you’d no longer have this rather significant blight on our waterfront.”

That’s exactly what happened when Milwaukee tore down its Park Freeway in 2004, replacing it with a ground-level, six-lane, tree-and sidewalk-lined boulevard. New housing, shops and offices soon sprouted on the 24 acres of land left vacant by removing the highway.

The announcement alone of the Embarcadero’s planned demolition caused nearby land values in San Francisco to shoot up almost 300 per cent.

It’s "totally the story you hear over and over again," said McCahill. "Freeways are bad for the city, detract from the land value, chop it up and wreck the built environment."

Pavement for roads and parking takes up 30 to 40 per cent of the average area of a city, said Holloway. With the value of urban land so high, it should be put to better use.

And if you want to have a vibrant, walkable, bikeable, environmentally friendly city, you need to get some cars out of dense urban areas because there’s just not enough space, he said.

Car travel in the U.S. peaked in about 2005 and has been declining ever since. "This is pretty clearly the new trend,” he said, especially among the young. “People are looking for dense cities where transit and walking and biking are the alternatives."

But if the indecision continues much longer, Torontonians should be prepared to dig deep into their pockets. It will cost an estimated average of $50 million per year over the next decade just to keep the elevated highway from falling down.