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.
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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.
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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.
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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.
It started out as it often does through a chance encounter with a roadmap anomaly. I happened to be examining a stretch of highway online. Then I spied an uncharacteristically wide split between the westbound and eastbound lanes of Interstate 84 directly outside of Pendleton, Oregon.
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It seemed quite remarkable. A mountain ridge forced opposing lanes to split and separate by an unusual distance. I used mapping tools to measure a line directly across the opening to estimate the greatest separation, which I calculated at around 1.7 miles (2.7 kilometers). This required a level of subjectivity. I attempted to measure between equivalent points on opposing lanes, measured almost horizontally in this instance. Obviously longer distances could be calculated by angling the line. That felt like cheating though. I decided to stick with my original estimate, giving or taking a small amount to account for eyeball-level accuracy, and wondered whether I could discover roads with greater separations.
Likely candidates went by different names such as
duel carriageway, freeway, motorway or divided highway, based upon linguistic variations of English-speaking nations. Likewise the separation between opposing lanes might be called a central reservation in the United Kingdom or a median strip in the United States, as examples. These terms could be mixed-and-matched to target online searches for better candidates.
Let’s dispel with the knee-jerk candidate right away.
Exibir mapa ampliado
An Intertubes mythology has coalesced around Brasília’s Monumental Axis ("Eixo Monumental"). This impressive roadway defined a core for Brazil’s capital city, a feat certainly worthy of recognition. This also created an uncorroborated notion that Monumental Axis was either the widest road or the widest central reservation on the planet. Clearly it is neither. I measured the median at 0.25 miles (0.4 km). That’s a wide spot for Brazil perhaps although completely unremarkable when compared to the Pendleton split.
I wasn’t the first to ponder this question. Others blazed a trail before me and recorded numerous instances, including the Pendleton example I felt so smug about "discovering" a few days ago. A roadfan discussion and an FAQ proved to be particularly helpful so I stole from those sources liberally. Examples going forward should be ascribed to people who mentioned them there. I was too lazy to find any other instances on my own.
My crude measurements suggested co-champions, one in Canada and one in México.
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The Trans-Canada Highway presented a paradox, a 2.6 mile (4.2 km) separation for no apparent geographic reason, located outside of Ernfold, Saskatchewan. There weren’t any mountains to bypass. Muskeg wouldn’t be an issue this far south. I did notice a number of small lakes and ponds within the vicinity although those should have been negotiated with ease by highway construction crews.
I may have found the answer. The original highway, now the westbound lanes, swung to the north and passed through Ernfold. The eastbound lanes came later. Those lanes took a more direct path, avoiding further traffic through a residential area while reducing construction costs.
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Down along the border between México and the United States, a common geographic formation created dueling companion instances with the more impressive one located in México.
I measured the Interstate 8 median strip east of San Diego, California at 1.5 miles (2.4 km). The distance between opposing lanes of Mexican Federal Highway 2D as it stretched from Tijuana to Mexicali came in at around 2.6 miles (4.2 km). That was the same as the Canadian example, once again within the margin of error of eyeball precision. I am sure one or the other occurrence could claim the crown with improved criteria and measurement.
One other United States location often surfaced in discussions, a stretch of Interstate 24 outside of Monteagle, Tennessee (map). I measured the width of the median at 1.7 miles (2.7 km), the same as Pendleton, so I’d call these a tie for the greatest US distance unless someone finds a better location.
Sometimes examples from the United Kingdom surfaced. They did not compare favorably.
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The M6 at Shap near Junction 39 received frequent attention. One source noted that " Junction 39 is the highest junction on the M6 being less than half a mile from Shap summit, the highest point on the M6." That would seem promising. I measured it at 0.2 miles (0.32 km) which was even as much as Brazil’s Monumental Axis. Others suggested the A611 at Annesley (map). The central reservation appeared to have a similar width. They were both noteworthy for the UK although neither contended for the world title.
Canadian and Mexican examples, both with 2.6 mile (4.2 km) median strips, were the best that I could find during my cursory search. Certainly we can do better.
Regular readers of the Twelve Mile Circle seem to enjoy vicarious road challenges: shortest routes, fastest times, greatest distances over a specific time, and things of that nature. I featured the quickest highway path from México to Canada a few weeks ago. Now I’d like to explore the other direction across the United States, from the Atlantic Ocean to the Pacific Ocean within the Lower 48. What is the quickest route and how long should it take for a theoretical driver obeying posted speed limits?
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It might help narrow the possibilities by examining the shortest line "as the crow flies" and then compare that result to the Interstate highway system to craft an approximate alignment. The United States Geological Survey (USGS) specifies that line as running from "approximately 10 miles south of Brunswick, GA" to "approximately 12 miles south of San Diego, CA." That’s a distance of 2,089 miles (3,362 kilometres). One may quibble that the line runs across a small corner of Baja California, México and whether it truly "counts" or not. It doesn’t matter much to me because I’ll keep the most similar highway route within the United States regardless.
Google disagrees slightly with the distance, returning a value of 2,091.83. It might have to do with the endpoints. The USGS didn’t provide exact latitude/longitude coordinates. I had to make an educated guess about where to drop a pin in Brunswick and San Diego even though each covers considerably more than a single point, and then head a designated number of miles south. It’s almost like trying to follow a pirate map. That came to the southern tip of Jekyll Island, Georgia and a couple miles north of the Mexican border. Also Google isn’t always 100% exact. I’ll consider the mileage discrepancy within an acceptable margin of error considering the uncertainties.
I also plotted the longest coast-to-coast line across the Lower 48, from West Quoddy Head, ME to Point Arena, CA. USGS said it was 2,892 miles (4,654 km). Google estimated 2,892.91. No complaints there. This has nothing to do with the rest of the article, however. I just wanted to see both lines on the same map.
The lesson I learned from the México-to-Canada discussion was that I don’t need to examine a slew of alternatives if someone else has already done the heavy lifting. 12MC reader Brian Casey mentioned the Iron Butt Association, a group of motorcycle enthusiasts who love to take extremely long road trips. I was already familiar with the group because I knew someone who participated in their 2011 Iron Butt Rally. However, I was less familiar with some of their individual ride certifications.
One of the certifications that riders can earn, as Brian Casey noted, was driving between México and Canada in either direction in less than twenty four hours. Did they have a similar certification for coast-to-coast travel, I wondered? Why yes, the Iron Butt Association issued a challenge called the 50CC Quest.
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It was designed for those riders not wanting to make the New York to San Francisco run yet looking for a challenge for crossing the country from coast to coast. You may choose any two coast cities (obviously, one on the Atlantic Ocean and the other on the Pacific Ocean) you wish (Jacksonville, Florida to San Diego, California is the most popular)… Your ride needs to be completely documented and cross the United States from coast to coast in 50 hours or less.
Notice the operative phrase: "Jacksonville, Florida to San Diego, California is the most popular." It followed, naturally, that people behaving rationally would select the quickest possible route. They have only 50 hours. The favored route follows Interstate 10 for most of its length, then Interstate 8 from the western half of Arizona and across California. Someone departing from Brunswick, Georgia would have to go through Jacksonville anyway, so Jacksonville is the better place to begin the journey.
The theoretical shortest straight line distance as noted above was 2,089 miles (3,362 km). The shortest highway distance turned out to be 2,359 miles (3,796 km) and Google said it could be done in 33 hours (recognizing that Google is conservative). This makes the 50CC Quest and its 50 hour limit quite feasible, assuming one has an iron butt.
Sure, I could try to find a quicker route. Why bother though? It’s already been crowdsourced and I’m happy to leave it at that.