# Why aren't there more tunnels? **URL:** \ **Category:** Factual Questions\ **Created:** [October 4, 2012, 8:28pm UTC](https://boards.straightdope.com/t/why-arent-there-more-tunnels/636739 "2012-10-04T20:28:49Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![kayaker](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kayaker/32/441_2.png) [@kayaker](https://boards.straightdope.com/u/kayaker)\ **Post date:** [October 6, 2012, 12:11pm UTC](https://boards.straightdope.com/t/why-arent-there-more-tunnels/636739/21 "2012-10-06T12:11:07Z")
> [@Zeriel](#): > > My experience with Pittsburgh suggests that a possible reason is that drivers get nervous in tunnels and slow down for no appreciable reason, causing traffic backups for miles in the approach that dissipate literally instantly at the other end of the tunnel. Preach it! There is a sign before the Squirrel Hill tunnel that says “Maintain Speed Through Tunnel”. I’ve always wanted to enter the tunnel at 55, then ram the driver going 45. My defense would be that I was obeying posted signage. ---
**Author:** ![Zeriel](https://avatars.discourse-cdn.com/v4/letter/z/58956e/32.png) [@Zeriel](https://boards.straightdope.com/u/Zeriel)\ **Post date:** [October 8, 2012, 3:55am UTC](https://boards.straightdope.com/t/why-arent-there-more-tunnels/636739/22 "2012-10-08T03:55:11Z")
> [@kayaker](#): > > Preach it! There is a sign before the Squirrel Hill tunnel that says “Maintain Speed Through Tunnel”. > > I’ve always wanted to enter the tunnel at 55, then ram the driver going 45. My defense would be that I was obeying posted signage. What’s especially worse is that all those idiots slow down for the tunnel and then jump right back up to 65 just in time for that Lovecraftian maze of on and off ramps on that damnable bridge. One could probably get used to it if one lived there, but as a guy who goes to the triangle maybe six times a year, it’s a gigantic pain in my ass. =P ---
**Author:** ![sitchensis](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sitchensis/32/4892_2.png) [@sitchensis](https://boards.straightdope.com/u/sitchensis)\ **Post date:** [October 8, 2012, 4:45am UTC](https://boards.straightdope.com/t/why-arent-there-more-tunnels/636739/23 "2012-10-08T04:45:21Z")
All these posts and nobody has mentioned that shot rock is a valuable commodity. When close to the project area shooting a load of rock is a good thing. If you’re putting a three foot lift of fill on your road bed, you need a lot of shot rock to finish the job. Yes, in some areas you may have too much rock but that is usually calculated from the road profiles. ---
**Author:** ![Isamu](https://avatars.discourse-cdn.com/v4/letter/i/7c8e57/32.png) [@Isamu](https://boards.straightdope.com/u/Isamu)\ **Post date:** [October 8, 2012, 10:22am UTC](https://boards.straightdope.com/t/why-arent-there-more-tunnels/636739/24 "2012-10-08T10:22:49Z")
Here’s a video I made driving across Japan from the east coast to the west coast. I made it primarily because I was just shocked at the sheer number of tunnels in Japan. Australia, where I was born, hardly has any tunnels because the land is, with few exceptions, flat. [![](https://i.ytimg.com/vi/DN6U1GWQWQs/hqdefault.jpg "xf73ldep765.avi") ](https://www.youtube.com/watch?v=DN6U1GWQWQs) ---
**Author:** ![Hari\_Seldon](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/hari_seldon/32/5173_2.png) [@Hari\_Seldon](https://boards.straightdope.com/u/Hari_Seldon)\ **Post date:** [October 8, 2012, 12:12pm UTC](https://boards.straightdope.com/t/why-arent-there-more-tunnels/636739/25 "2012-10-08T12:12:27Z")
Back in the mid 19th century, the Penna RR built a bunch of tunnels through mountains, then discovered there was no way to ventilate them (remember steam locomotives?) and gave up and built things like the famous Horseshoe Curve ([Horseshoe Curve (Pennsylvania) - Wikipedia](http://en.wikipedia.org/wiki/Horseshoe_Curve_%28Pennsylvania%29)) as an alternative. The tunnels sat empty until the Penna Tpk was built in the 1930s (I believe it was a WPA project originally). Between Philadelphia and Pittsburgh there were originally 7 tunnels. But they were only two lanes through the tunnels, although the turnpike was otherwise four lanes. As traffic increased, they became congested and were mostly abandoned. I haven’t driven that in years; maybe they have all been bypassed. There is at least one tunnel on the NE extension, but it was built as 4 lanes. The fact remains that they are expensive to build, expensive to maintain, and expensive to operate. ---
**Author:** ![IvoryTowerDenizen](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ivorytowerdenizen/32/17937_2.png) [@IvoryTowerDenizen](https://boards.straightdope.com/u/IvoryTowerDenizen)\ **Post date:** [October 8, 2012, 12:23pm UTC](https://boards.straightdope.com/t/why-arent-there-more-tunnels/636739/26 "2012-10-08T12:23:56Z")
> [@Zeriel](#): > > What’s especially worse is that all those idiots slow down for the tunnel and then jump right back up to 65 just in time for that Lovecraftian maze of on and off ramps on that damnable bridge. One could probably get used to it if one lived there, but as a guy who goes to the triangle maybe six times a year, it’s a gigantic pain in my ass. =P You’re bringing back nightmares from my Pgh days! I remember at one point they had flagmen waving people along to encourage them not to slow down at the tunnel. So what’d everyone do? Slow down even more, since there were flagmen, something must be wrong! :smack: ---
**Author:** ![hibernicus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/hibernicus/32/2802_2.png) [@hibernicus](https://boards.straightdope.com/u/hibernicus)\ **Post date:** [October 8, 2012, 1:34pm UTC](https://boards.straightdope.com/t/why-arent-there-more-tunnels/636739/27 "2012-10-08T13:34:43Z")
> [@Isamu](#): > > Here’s a video I made driving across Japan from the east coast to the west coast. I made it primarily because I was just shocked at the sheer number of tunnels in Japan. > > Australia, where I was born, hardly has any tunnels because the land is, with few exceptions, flat. > > [http://www.youtube.com/watch?v=DN6U1GWQWQs](http://www.youtube.com/watch?v=DN6U1GWQWQs) I am also amazed by the countless road tunnels in Japan. Not just on the drive to the Sea of Japan coast or to Tokyo - even on the relatively short drive from here into Nara prefecture you’ll pass through a lot of long tunnels. Similar to your experience, Ireland, where I come from, had no road tunnels at all when I grew up there. The first road tunnel was opened in 1999 and the first bored tunnel in 2007. ---
**Author:** ![yabob](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/yabob/32/2821_2.png) [@yabob](https://boards.straightdope.com/u/yabob)\ **Post date:** [October 8, 2012, 2:35pm UTC](https://boards.straightdope.com/t/why-arent-there-more-tunnels/636739/28 "2012-10-08T14:35:01Z")
One thing which hasn’t been mentioned is seismic considerations. While far from earthquake proof, and seismic factors need to be considered in their design, tunnels may fare better than bridges in an earthquake. > **[Tunnels - Structures - Bridges & Structures - Federal Highway...](https://www.fhwa.dot.gov/bridge/tunnel/)** > [@](#): > > Tunnels, in general, have performed better during earthquakes than have above ground structures such as bridges and buildings. Tunnel structures are constrained by the surrounding ground and, in general, can not be excited independent of the ground or be subject to strong vibratory amplification, such as the inertial response of a bridge structure during earthquakes. Another factor contributing to the reduced tunnel damage is that the amplitude of seismic ground motion tends to reduce with depth below the ground surface. Adequate design and construction of seismic resistant tunnel structures, however, should never be overlooked, as moderate to major damage has been experienced by many tunnels during earthquakes, as summarized by Dowding and Rozen (1978), Owen and Scholl (1981), Sharma and Judd (1991), and Power et al. (1998), among others. I presume this may be a factor in favoring tunnels in earthquake country. I have no idea whether this helps to explain Japan at all, but Japan does get a lot of earthquakes. I do remember that in the Loma Prieta quake, with the Cypress collapse, the section falling out of the Bay Bridge, and so on, the Transbay tube (carries BART, not auto traffic) was undamaged and opened within a day. ---
**Author:** ![suranyi](https://avatars.discourse-cdn.com/v4/letter/s/e36b37/32.png) [@suranyi](https://boards.straightdope.com/u/suranyi)\ **Post date:** [October 8, 2012, 5:18pm UTC](https://boards.straightdope.com/t/why-arent-there-more-tunnels/636739/29 "2012-10-08T17:18:27Z")
> [@Isamu](#): > > Here’s a video I made driving across Japan from the east coast to the west coast. I made it primarily because I was just shocked at the sheer number of tunnels in Japan. > > Australia, where I was born, hardly has any tunnels because the land is, with few exceptions, flat. > > [http://www.youtube.com/watch?v=DN6U1GWQWQs](http://www.youtube.com/watch?v=DN6U1GWQWQs) The highway in Italy along the coast near Genoa is like that too. Dozens of tunnels. I think it was more tunnel than open. ---
**Author:** ![Tom\_Tildrum](https://avatars.discourse-cdn.com/v4/letter/t/e95f7d/32.png) [@Tom\_Tildrum](https://boards.straightdope.com/u/Tom_Tildrum)\ **Post date:** [October 8, 2012, 5:40pm UTC](https://boards.straightdope.com/t/why-arent-there-more-tunnels/636739/30 "2012-10-08T17:40:58Z")
> [@phreesh](#): > > Are there any tunnel experts out there? I can’t say I’m a tunnel expert, but I have been called a boring man. ---
**Author:** ![FluffyBob](https://avatars.discourse-cdn.com/v4/letter/f/ecb155/32.png) [@FluffyBob](https://boards.straightdope.com/u/FluffyBob)\ **Post date:** [October 8, 2012, 6:05pm UTC](https://boards.straightdope.com/t/why-arent-there-more-tunnels/636739/31 "2012-10-08T18:05:45Z")
Tunnels are very dangerous death traps in the event of a fire, ventilation is not a a small issue and they are frickin expensive to build. ---
**Author:** ![Enderw24](https://avatars.discourse-cdn.com/v4/letter/e/ba9def/32.png) [@Enderw24](https://boards.straightdope.com/u/Enderw24)\ **Post date:** [October 8, 2012, 6:24pm UTC](https://boards.straightdope.com/t/why-arent-there-more-tunnels/636739/32 "2012-10-08T18:24:20Z")
That’s what America needs. Coast to coast Big Digs. ---
**Author:** ![kenobi\_65](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kenobi_65/32/13178_2.png) [@kenobi\_65](https://boards.straightdope.com/u/kenobi_65)\ **Post date:** [October 8, 2012, 6:24pm UTC](https://boards.straightdope.com/t/why-arent-there-more-tunnels/636739/33 "2012-10-08T18:24:45Z")
One other factor in the difference between train tunnels and roadway tunnels is that railroads, by and large, try to avoid steep grades…roads (especially in mountainous areas) can get away with grade percentages that conventional railroads simply cannot. Additionally, roads can make far tighter turns than railroad tracks, allowing for the use of switchbacks and hairpin turns. So, in a given location, a tunnel may be the only way to route a railroad through the area, while a roadway can go over the obstacle in question. ---
**Author:** ![Ispolkom](https://avatars.discourse-cdn.com/v4/letter/i/e47774/32.png) [@Ispolkom](https://boards.straightdope.com/u/Ispolkom)\ **Post date:** [October 8, 2012, 6:32pm UTC](https://boards.straightdope.com/t/why-arent-there-more-tunnels/636739/34 "2012-10-08T18:32:56Z")
> [@Hari\_Seldon](#): > > Back in the mid 19th century, the Penna RR built a bunch of tunnels through mountains, then discovered there was no way to ventilate them (remember steam locomotives?) and gave up and built things like the famous Horseshoe Curve ([Horseshoe Curve (Pennsylvania) - Wikipedia](http://en.wikipedia.org/wiki/Horseshoe_Curve_%28Pennsylvania%29)) as an alternative. The tunnels sat empty until the Penna Tpk was built in the 1930s (I believe it was a WPA project originally). Between Philadelphia and Pittsburgh there were originally 7 tunnels. But they were only two lanes through the tunnels, although the turnpike was otherwise four lanes. As traffic increased, they became congested and were mostly abandoned. I haven’t driven that in years; maybe they have all been bypassed. There is at least one tunnel on the NE extension, but it was built as 4 lanes. The fact remains that they are expensive to build, expensive to maintain, and expensive to operate. No, the Pennsylvania Turnpike was built using tunnels of the abortive [South Pennsylvania Railroad](http://en.wikipedia.org/wiki/South_Pennsylvania_Railroad), a New York Central project to break the Pennsylvania Railroad’s lock on the Pittsburgh-Philadelphia market. The problem wasn’t the use of tunnels with steam locomotives, as there were any number of solutions to that. The problem was protecting the railroad owners’ profits. ---
**Author:** ![Hari\_Seldon](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/hari_seldon/32/5173_2.png) [@Hari\_Seldon](https://boards.straightdope.com/u/Hari_Seldon)\ **Post date:** [October 8, 2012, 9:39pm UTC](https://boards.straightdope.com/t/why-arent-there-more-tunnels/636739/35 "2012-10-08T21:39:25Z")
> [@Ispolkom](#): > > No, the Pennsylvania Turnpike was built using tunnels of the abortive [South Pennsylvania Railroad](http://en.wikipedia.org/wiki/South_Pennsylvania_Railroad), a New York Central project to break the Pennsylvania Railroad’s lock on the Pittsburgh-Philadelphia market. The problem wasn’t the use of tunnels with steam locomotives, as there were any number of solutions to that. The problem was protecting the railroad owners’ profits. It just goes to show how wrong you can be to repeat “what everybody knows”. So why didn’t the RR get built? ---
**Author:** ![Zebra](https://avatars.discourse-cdn.com/v4/letter/z/c0e974/32.png) [@Zebra](https://boards.straightdope.com/u/Zebra)\ **Post date:** [October 8, 2012, 9:53pm UTC](https://boards.straightdope.com/t/why-arent-there-more-tunnels/636739/36 "2012-10-08T21:53:17Z")
Have you ever read the Lincoln Tunnel scene in Stephen King’s The Stand? Good enough reason to never make any more tunnels. ---
**Author:** ![Jaguars](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jaguars/32/5879_2.png) [@Jaguars](https://boards.straightdope.com/u/Jaguars)\ **Post date:** [October 9, 2012, 3:38am UTC](https://boards.straightdope.com/t/why-arent-there-more-tunnels/636739/37 "2012-10-09T03:38:48Z")
Disclaimer: This is just background engineering stuff I learned for my job. There are a few main reasons that there aren’t more tunnels. The first is the method of construction. A tunneling machine is a specialised machine that costs several times the equipment used on the surface construction. Not only that, but unless your construction contractor evisages a steady supply of tunnel construction in the future, the tunnel machine will need to pay itself off in the one project, where surface excavators can just be moved on to the next project (Or can be sold easily and quickly). They are also slower because there are only two possible points can be done, at the tunnel heads. Every extra day of work costs due to greater labour, plant and finance costs. Drilling and blasting is even slower and more dangerous and the cheapest method, cutting and covering obviously can’t be done under a mountain range. Second is the unknowns. You can survey a surface route well, but it’s hard to know what sort of rock a long tunnel will encounter, even with geotech investigations. If you end up hitting rock too hard for your tunnel machine then you have a very, very expenive mistake. Fill from surface cuts can be used on embankments further down the road, but a (long) tunnel will produce a surplus of fill to get rid of. It can be sold but costs money to truck out. Another thing is that the current road is likely to have been upgraded since times when travellers were on foot. If the route was establised by the native indians and later made into a cart route and then into a highway, the costs and effort have been spread over hundreds of years. To be cost effective, a tunnel has to save a huge amount of time or distance, which is why really long tunnels under the swiss alps can be built. So why is the railway exempt from all this? Because grade is king, and because at the time that they were built, the costs were different. These days two guys with a digger and a truck can move a huge amount of material cheaply and safely, They can move much more earth/rock before it becomes worthwhile to build a tunnel to save on earthmoving costs. If today’s tunnelling boring machines could have been used in the 1800’s, It would be quite likely that there would be rail tunnels going right under many mountain ranges. Hopefully that makes things clearer and not worse 😉 ---
**Author:** ![Floater](https://avatars.discourse-cdn.com/v4/letter/f/dc4da7/32.png) [@Floater](https://boards.straightdope.com/u/Floater)\ **Post date:** [October 9, 2012, 8:07am UTC](https://boards.straightdope.com/t/why-arent-there-more-tunnels/636739/38 "2012-10-09T08:07:27Z")
> [@suranyi](#): > > The highway in Italy along the coast near Genoa is like that too. Dozens of tunnels. I think it was more tunnel than open. I have no idea about the road in that area but the railroad west from Genoa is like this and the railroad East of town is in a tunnel most of the way to La Spezia. You can really say, if you have gone that way, that you have travelled through Cinque Terre. ---
**Author:** ![Johanna](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johanna/32/8318_2.png) [@Johanna](https://boards.straightdope.com/u/Johanna)\ **Post date:** [October 9, 2012, 1:21pm UTC](https://boards.straightdope.com/t/why-arent-there-more-tunnels/636739/39 "2012-10-09T13:21:16Z")
> [@Jaguars](#): > > Hopefully that makes things clearer and not worse 😉 It did, thanks. Nobody thinks about the hidden costs until they have to deal with them. ---
**Author:** ![hibernicus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/hibernicus/32/2802_2.png) [@hibernicus](https://boards.straightdope.com/u/hibernicus)\ **Post date:** [October 9, 2012, 1:37pm UTC](https://boards.straightdope.com/t/why-arent-there-more-tunnels/636739/40 "2012-10-09T13:37:33Z")
> [@the\_diego](#): > > Excavating expense (more than $1,000 for every meter advanced and that’s just the bare excavation,) This number seems like an incredible underestimate to me. It would imply that you could bore a 1 km tunnel for $1 million. Isn’t that way low, even for the bare excavation? [Previous page](https://boards.straightdope.com/t/why-arent-there-more-tunnels/636739.md?page=1) [Next page](https://boards.straightdope.com/t/why-arent-there-more-tunnels/636739.md?page=3)