How Low Can it Go?

I stumble across the most fascinating bits of information in unexpected places. It happened this time as I examined the unusually-wide median strip between the eastbound and westbound lanes of Interstate 8 in southern California. I learned of a nearby oddity further down the highway while reviewing various roadfan websites.

A motorist will encounter the lowest overland elevation in the entire Interstate Highway System just to the east of the extreme central reservation I’d discovered earlier. It is listed as 52 feet (16 meters) below sea level by the U.S. Government’s Federal Highway Administration.

It’s not the lowest elevation of any road of any type within the U.S. — that’s Badwater Road in Death Valley which provides access to the lowest public restroom in North America (~ -282 ft, -86 m) — just the lowest natural point of elevation in the Interstate Highway System. It’s still pretty impressive, though.

View Larger Map

This happens in the vicinity of Exit 107 where I-8 crosses the New River. Notice the channel. The road dips down here as it crosses the river over a short bridge. Where, I wondered, could the New River be flowing if it was already more than fifty feet below sea level here? Certainly it would not be flowing to the sea. It much be part of an endorheic basin, and indeed that is the case.

The New River begins in Baja California, Mexico where it’s known as the Río Nuevo. It passes through the wonderfully conjoined portmanteau cities of Mexicali and Calexico. From there it flows under the I-8 bridge west of El Centro, and on to the Salton Sea. The surface elevation of the Salton Sea is -226 ft (-69 m) so whatever flows along the New River won’t leave the Salton Sea on its own unless it’s able to evaporate.

View Larger Map

That’s a problem. This Street View image from the point of lowest Interstate elevation shows one of the most polluted bodies of water in the nation. Sewage, pesticide-laden agricultural runoff, and industrial waste from businesses located along the ditch then dump into a basin without an outflow. Toxins and pathogens collect in extreme concentrations, creating a most foul situation. Those driving at high speed along I-8, crossing this point of lowest elevation, likely never consider the drawbacks of this dubious honor.

Let’s put one more asterisk onto the claim. There are other places along the Interstate Highway Systems with a lower elevation. However, they are located in tunnels. A similar situation exists in Canada.

View Larger Map

The Intertubes claims that the Fort McHenry Tunnel carrying I-95 traffic through Baltimore, Maryland represents the absolutely lowest Interstate elevation at 107 ft (33 m) below sea level. It passes in close proximity to historic Fort McHenry, as implied by the name, the battlefield site inspiring the Star Spangled Banner. It then drops below Baltimore Harbor. I’d post a Street View image except that the interior of a tunnel isn’t exactly the most exciting scenery available (check for yourself if you must).

While the exalted position of the Fort McHenry tunnel seemed to be conventional wisdom for the cyberspace masses, it was not the only candidate offered. I discovered numerous other claims. I could not, however, nail-down a definitive source. Another option included the I-93 Thomas P. "Tip" O’Neill Tunnel, part of the Big Dig project in Boston, Massachusetts. The I-64 Hampton Roads Bridge-Tunnel in Virginia was also mentioned frequently. I know we have several roadfans who read 12MC regularly so hopefully someone can provide a proper citation and we can put these issues to rest. I’ve driven through all three of these tunnels so I’m covered no matter how it turns out. Funny, I never realized I was experiencing a true geo-oddity during any of my transits.

I’ve never driven on I-8 through California though. I look forward to experiencing both the wide median and the lowest overland elevation someday.

Over the Road

I’ve been captivated by a Street View image posted by reader Katy in a comment on my recent Tunnels, Bridges, Lifts and Inclines article. It shows a canal going over a road in the Netherlands. The interesting aspect, to me, is that a viewer can determine the actual depth of the canal. Highway engineers were kind enough to paint the canal enclosure in a black-and-white checkerboard pattern.

I’m not sure why a massive concrete half-pipe filled with boats stirs my imagination. It does. It also got me thinking about other structures extending above roads. There are literally thousands of examples. Please feel free to suggest your own local favorites.


View Larger Map

Toll roads hold a captive audience but highway authorities have to meet certain basic driver needs to keep the meter running. It’s more cost effective to provide a single service area within the highway median, for traffic moving in both directions. That’s easier in a rural area where land is cheap and plentiful but a bit more difficult in an urban environment. The Illinois Tollway solved this problem by putting travel plazas, in this instance the Tri-State Tollway’s O’Hare Oasis near Chicago, above the motorway.

It’s not exactly fine dining but I can see a Starbucks and an Auntie Anne’s through the window, along with some tables and chairs (and is that someone sitting there?). Maybe this is more properly a food court but I’ve noticed others in my journeys that are closer to traditional restaurants. I selected this image because I’ve actually stopped here. I also like that it’s called an Oasis. It puts images of camels, sand dunes and palm trees in my mind in complete contrast to what is actually found there. Rare examples of bureaucratic creativity deserve to be rewarded.

Shopping Mall

View Larger Map

Head over to Cheltenham (near Melbourne) in Victoria, Australia, and one can experience a shopping mall built across the Nepean Highway. This is the Westfield Southland Shopping Centre. The Intertubes imply that the eastern portion was constructed first and the western portion was built as an annex later.

Westfield Southland Cheltenham
SOURCE: Westfield Southland.

Oh look, here’s a shop located directly above the roadway. Have any of our Australian readers from the Melbourne area experienced this shopping centre in person?


View Larger Map

The Great Platte River Road Archway Museum in Kearney, Nebraska may be the only museum built over a roadway. That means I’m too lazy to look for other examples but it sounds plausible and I’ve offset it with a qualifier. I was in Nebraska when this monument to frontier culture opened in 2000 although I didn’t have an opportunity to visit.

It’s not exactly located conveniently unless one happens to be driving through a vast empty expanse along Interstate 80. Actually, that’s the point. The state designed this attraction to tempt long-distance travelers so they would stop in Kearney and leave a little money behind for the local economy. There aren’t many economic opportunities way out in the wide open spaces of the Great Plains.


View Larger Map

I could have chosen hundreds of examples of parks over roadways. It seems to be in vogue with urban planners at the moment along with everything "green." I selected parklands created by the monumental Big Dig undergrounding of the Interstate 93 Central Artery in Boston, Massachusetts.

Everything associated with the Big Dig happened on an epic scale including the creation of green space right at city center, where an ugly elevated motorway once stood. The 15 acres of new parkland has been dubbed the Rose Kennedy Greenway and represents the final phase of the project: "When Boston’s Big Dig project plunged previously elevated roadways underground, the city found itself rich in prime urban land. Community and political leaders seized the opportunity to enhance Boston’s city life by providing additional parks and gardens to connect some of its oldest, most diverse and vibrant neighborhoods."

Office Building

A Road Runs Through It
SOURCE: Flickr (user caribb); under Creative Commons Attribution-NonCommercial-NoDerivs 2.0 Generic License

The Gate Tower Building in Osaka, Japan received significant Internet fanfare a couple of years ago to the point where it became a bit of a cliché. Nonetheless I still love the notion of a freeway ramp barreling directly through the gut of an office building. I couldn’t get a decent angle from Google Maps (it’s the circle) so I’ve lifted the above image from Flickr, with attribution. This situation is already well-covered by other sources so I’ll move along.


View Larger Map

A surprising number of airports have roads that run beneath them. Logically, it makes sense: passengers want convenient locations but airports require lots of land. I selected the Manchester Airport in the United Kingdom in this instance. As noted in, it has "a road (the A538 Wilmslow Road) that passes under both runway 23R/05L (and its parallel taxiway) and 23L/05R,” which makes it a particularly remarkable example.