Faster Roads Gobble Up More Real Estate


It’s a pretty striking contrast, isn’t it? On the left, Florence, Italy, birthplace of the Renaissance. On the right, Atlanta, Georgia, home of the 23-lane freeway.

This was the central illustration in an illuminating discussion of how roads designed for high-speed car travel devour our landscapes and devastate their value. Steve Mouzon, principal at Miami’s Mouzon Design and author of The Original Green blog, argues in Better Cities and Towns that our fondness for wide, high-speed roads simply takes up too much space.

He compares Seaside, Florida, a community with a more traditional street pattern, with the landscape surrounding an interchange in Miami. In the former, 80.5 percent of the land is available for development; in the latter only 62 percent — an astonishing 34 percent of the land is consumed by roads.

Fast, highway-like roads hog land in four primary ways, Mouzon explains:

Curves — Increasing speed a little bit requires a big increase in the size of curves. At 20 miles per hour, any car can handle a curve with a 15-foot radius, so you’d think that tripling the speed would triple the radius, right? Wrong. At 60 miles per hour, curve radii are usually a few hundred feet, not the 45 feet you might guess.

Lane width — Faster roads need wider lanes. An eight-foot lane can handle 20 mile per hour traffic, but at highway speeds, you need 12 foot lanes [to give fast-moving drivers a wider berth].

Medians and shoulders — High-speed roads need wide medians and shoulders because a car can roll hundreds of feet beyond the point of collision or loss of control when it is traveling at highway speeds.

Number of lanes — It makes no sense to use all that land on either side for a two-lane highway, so high-speed thoroughfares usually have at least four lanes, often several more.

Equally pernicious are high-speed roads’ influence on culture, Mouzon says, noting that “the entire Duomo (the cathedral in the center of Florence that arguably began the Renaissance) could fit in one of the inner loops of the interchange.” It seems safe to assume that America’s next great artistic movement will have nothing to do with the Atlanta interchange.

Apparently oblivious to the costly side effects of the highway-ification of local roads, AASHTO last week issued a report recommending wide, straight roads as the best way to promote safety for older motorists. Ugh.

 

  • icarus12

    Not to argue with your central premise re land use and the gobbling freeway . . . but the use of ANY Italian city and its nearby highways as an example of good transportation planning is absurd, even obscene.  I am just back from nearly a month in Italy, some of that spent traveling by car between cities, though not in them.  A nightmare all the way around.  Italy has lots of highways, lots of roads, and lots of driving.  Bad driving.  Chaos, corruption, bribery, non-enforcement, extreme hazard, a total disregard for rules or pedestrian or driver safety — that’s Italian driving practice.  I have never seen anything like it in all my travels.

    Florence has walled off its central area to cars without permits.  Fine and good.  But guess what?  There is no clear signage as to how to avoid going into the so-called restricted area.  No way to find the periphery parking lots by following signs.  We spent 2 hours going round and round, trying to avoid the 100 Euro fine for crossing the invisible line.  And that’s 100 Euros per crossing, so one could rack up several of them in confusion.

    Want to know what else Italy does not do?  Employ highway patrol or police to enforce traffic laws.  Every 10th vehicle had a burned out headlight.  Speed limits are almost never observed. Drivers routinely drive using two highway lanes simultaneously. Cars zoom through Rome’s streets at 50-60 mph with pedestrians crossing inches in front of the onslaught.  Heaven forbid a person trips — death.  Pompeii, a small place really, was gridlocked on a Saturday night from young people cruising, 1950s style, in tin can cars, honking and screaming to one another, nearly running down pedestrians.  The police watched laconically, declining to direct traffic.  Everybody just put up with the racket and pollution and shrugged.  What can one do with a government so corrupt, they seemed to think?

    Italy’s land use planning around cars is a lamentable mess.  Find another example to make your argument.

  • Guest

    sad icarus.  You made the great folly of bringing your american driving habits to a city where you could walk, ride a bike, or take a tram.  Let alone they have an excellent high speed rail network, and are supported by local and commuter trains.  

    Perhaps you missed the point that the best roads aren’t made for cars, but for people.

  • Anonymous

    An interesting article which touches on this with a comparison of the figure for various cities: http://oldurbanist.blogspot.com/2011/06/density-on-ground-cities-and-building.html

  • icarus12

    “Guest” — you are the sad one, because you neither read nor think clearly.  It was Italian driving habits and lack of enforcement that I was criticizing.  The hazards to pedestrians in Italian cities is shocking.  The hazards to drivers on pay-to-drive highways (a good thing, in my opinion) were also shocking.  None of that has anything to do with driving a car per se.  It has to do with the government failing to enforce safety rules.  And as for Florence failing to provide signage and means for drivers to park outside the city — that results in massive delays and more driving hours and lots more air pollution for drivers seeking to leave their cars outside the city and use public transit.

    Had you taken a minute to actually read what I wrote and think, you would have understood that.  But you are obviously a reactionary with a turnip for a brain.

  • RichardC

    icarus and Guest, let’s address the topic at hand instead of insulting one another.

    I think the point was not that Italy does a great job of policing, signage, or rule-abiding driving (no one is arguing they do), but that their centuries-old central cities pack an incredible amount of livable space, culture, beauty into the same space we instead fill with looping off-ramps and parking lots. Banning cars from the center city makes the streets of Florence a joy to walk around. And all that is true whether or not they have adequate signage to point you to a parking lot on the edge of the city.

  • icarus12

    RichardC, you are right about not getting into insults.  Sorry about that.  But the problem with showing Florence as an example is this: from an overhead view it looks like good land use.  But because of a lack of traffic enforcement, the drivers with permits in Florence still make walking and biking a whole lot more dangerous and unpleasant than necessary.  Compact land use space is a good start, but it is wholly inadequate if drivers are going to bully pedestrians in Florence and other cities.

  • Icarus you are not seeing the problem here. The problem is cars and our dependency on them gobbling up the landscape. In your car-dependence you were at odds trying to navigate a car-light landscape. They didn’t comport to your expectations, therefore they were wrong in your eyes. would you say the same if they didn’t have an airport at every destination?

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