The Top 2 longest straight roads in the world are:
#2 - A section of the Eyre Highway, which is part of the Australian National Highway, runs dead straight through the Nullarbor Plain in southwest Australia for 91.1 miles.
#1 - At just over 152 miles, the longest straight road in the world is the Haradh to Batha Highway in central Saudi Arabia. The actual road is 160 miles long, but a short section curves slightly northward in its eastern end to connect to north-south roads on the eastern coast of the country.
(I used the Ruler feature on Google Earth to get my measurements. They are accurate to within 1/10th of a mile.)
This is quite incorrect – highway engineers do deliberately make their roads non-straight.
At least, the Interstate System engineers did. Their studies showed that drivers tended to become inattentive, even to almost doze off (‘road hypnosis’) when the road is too straight for too long, with nothing for the driver to do. So they learned to build them as a series of gentle S-curves, going in a straight direction, but with slight curves along the way.
This is discussed in some detail in The Big Roads by Earl Swift, a history of the design & building of the US Interstate Highway system.
I have driven this stretch several times and just recently this past week of June 17th, 2013. I was never under the impression anyone considered this road the longest straight stretch of highway in the U.S. until I saw a special on Chan 4 in OKC. I googled it and Tomegee seems to be the only person in the U.S. who thinks Hwy 412 takes the top spot and his posts are the actual inspiration for the News piece.
From google earth or yahoo maps the highway does appear to be extremely straight as it follows the section line. It is quite straight but from my own eyes and personal experience I can say this road is not actually straight. It deviates from center quite often all though only by a few feet it is quite noticeable while driving.
From an engineering standpoint and a driver standpoint both of the Hwy 412 sections would be out of contention. The Hwy is poorly built (sways back and fourth) and there are several center lanes that are formed near intersections that must be navigated around.
My guess on the actual straightest lock-your-wheel/plum straight stretch of Hwy in the U.S. would have to be a newer interstate built with the latest technology and would span less than 30 miles.
The term ‘Razor’s Edge’ should never be used when talking about OK HWY 412. I about spit my drink up when I read that. Haha.
The reason for this is alleged to be the PA Turnpike. Since the initial stretch (Carlisle to Irwin) was built on the right-of-way of the South Pennsylvania Railroad, an abandoned railroad project about 50% completed, the road from the Blue Mountain Tunnel to Carlisle is a straight shot with nothing but small undulating hills. As a result, there were more accidents on this section than anywhere on the rest of the Turnpike, because of “highway hypnosis”. The later sections incorporated curves to prevent this from happening.
It’s an apocryphal story, but possible since the Turnpike was opened in 1940 and was “America’s First Superhighway”, existing long before the Interstate system and acting as the model for it.
It might not have been only the PA Turnpike, but a “straight line” highway was something that was already recognized to be a problem by the late 1940’s when the Garden State Parkway in NJ was being designed:
I didn’t realize my assertions had become “cause celebre” on Oklahoma City television. I’m quite flattered.
Addressing the criticism:
It’s an irrefutable fact that any drawn line (or, in this case, paved road) will be deemed not “perfectly straight” when placed under harsh enough scrutiny; it will have anomalies.
Driver 412 himself states that, even though Highway 412 “deviates from center quite often” it is “only by a few feet”. As a measure of compromise I will relax the rigidity of my statement to add “only deviating from the center line a few feet its’ entire length.”
The parameter I was judging the road’s straightness by was whether, by design, the road had any intentional curves or bends integrated into it the course of its length. I still contend both the 47-mile section between Boise City to west of Guymon, and the 65-mile section from Hardesty to just east of Slapout do not.
I don’t fully understand the phrase “swaying back and forth”. If it means the road has undulations in it, I don’t see how that would have any effect on its overall course. If that isn’t what is meant, I would appreciate some clarification.
I also don’t consider the fact “there are several center lanes that are formed near intersections that must be navigated around” as a reason Route 412 must be removed from contention.
The basic measure of a road’s straightness is determined by the path the road itself follows, not (in this case) the extremely minor deviations a driver must take to navigate it.
I’m all for a legitimate holder of “Longest Straight Road in the US” to measure up to a higher standard, but some realistic, reasonable allowances have to be made.
My response to 412 Driver (sorry for reversing your name in my previous post) to his comment “I googled it and Tomegee seems to be the only person in the U.S. who thinks Hwy 412 takes the top spot”:
The fact is, since I originally posted my comment here and on Roadside America over six months ago, no one has made any claim to have found a longer straight road anywhere in the United States.
Either everyone completely lost interest in the subject, or it was recognized that I may, very well, be right.
Additionally, I don’t think KFOR Channel 4 in Oklahoma City would send a reporter and cameraman almost 200 miles to Slapout, then drive the additional sections of Route 412 (totaling almost 140 miles), then devote airtime to broadcast the story if they hadn’t first done their research and found this to be viable and factual.
I imagine Russia might be a contender. From close to the center of St Petersburg all the way to Chudovo, there’s a 113 km straight stretch (not counting two slight turns around Tosno and a bunch of roundabouts. Google Maps. It runs along the railroad between Petersburg and Moscow, which is a straight line for a little over 400 miles (except, until 2001, for one bend known as ‘the Czar’s Finger’).
Roadwise, that’s the first that came to my mind, I’m sure there’s others that might be longer.
Wow, I didn’t think you would get butt hurt over this.
I can IRREFUTABLY say that these stretches of 412 are NOT the straightest in the US.
I misspoke. After now driving the Guymon to Boise City stretch over 20 times in the last month and the Hardesty to Slapout stretch 9 times. The deviations or anomalies as you call them are much more than a few feet. There are hundreds of sways in the 3-5ft area and then about 10-20 sections along the way that deviate well outside of plum. Again, from a pure engineering standpoint this road is terrible example of a razor’s edge straight road. To save on costs the road was constructed to follow the slopes of the gentle hills and creek valleys instead of leveling/grading it out to be straight. So its not like the wiggles are corrections for the curvature of the Earth, they are there to save money. This is exactly why this road can’t even be on the list. If you would use a live GPS map like the app WAZE, you can see the wiggles in the road along 412 very easily on the map. If you use Google Earth, Google Maps, or Yahoo the line is drawn straight.
About Channel 4, this is Oklahoma buddy and our News stations report on things like stray dogs getting hit on the highway and peach festivals in towns with less than 100 population. There isn’t anything going on and the 412 piece is extremely typical of what you will find during a newscast on a weekday.
In the end, the reporter wasn’t convinced and says he doesn’t know if Oklahoma can really make a claim to the longest straight stretch.
US 412 is the longest straightest stretch on a MAP, nothing else.
I also want to clarify something. You can insert two pins into a globe and connect a string between the two. Yes, the line hugs the curve of the globe but it doesn’t not deviate from left to right. There are sections of highway in this country that are plum straight and do not deviate from center whatsoever. 412 isn’t one of them.
