Skip to Content
Streetsblog USA home
Streetsblog USA home
Log In
Land Use

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.

Stay in touch

Sign up for our free newsletter

More from Streetsblog USA

Tuesday’s Headlines Are Running Hard

More political news: Today's top stories delve into Kamala Harris' record on climate change and Republicans' plans for the Trump administration if he returns to power.

July 23, 2024

State DOTs Could Fuel a Resurgence in Intercity Bus Travel

Private equity firms are killing off intercity bus companies. Will public agencies fill in the gaps?

July 23, 2024

GOP’s ‘Project 2025’ is ‘Based on a Lot of ignorance’

What does Transportation for America's Beth Osborne think of the transportation portion of the Heritage Foundation's playbook for a Trump presidency?

July 23, 2024

What a Surprise! Hochul’s Congestion Pricing Pause Helps Rich Suburban Drivers

Gov. Hochul's "little guys" certainly have big wallets. Meanwhile, the rest of us suffer with declining subway service and buses that are slower than walking. Thanks, Kathy.

July 22, 2024

Philadelphia Demands More Than ‘Flex-Post’ Protected Bike Lanes After Motorist Kills Cyclist

Pediatric oncologist Barbara Friedes was struck while biking on a "protected" path. Now, advocates are arguing that flex posts should be replaced with something far better.

July 22, 2024
See all posts