In the past private light rail WAS built into open spaces.
 

In the past private light rail WAS built into open spaces. The classic example is in Southern California where entire cities grew up around private rail transit.

No, in the 90s and the 21st Century rail transit and highway construction are built to differing standards. In Colorado, for example, CDOT rules. If any proposal is made to share ROW etc., with CDOT, one can expect to having work around what CDOT is going to do anyway (Those of you that have attended CDOT meetings over the years likely remember the noise and anger, and, also how years later the highway link was built as presented at the meetings, anyway.)

This can be seen on the Trex line, which, had the public transit element been more powerful, would have not had to follow such steep grades and nor have had to built such tight curvatures in response to I25 Interchanges (this is true on all I25 interchanges except for I25/University and I25 at I/225).

This, too, is visible on the Taj Mahal line, where the segment from Simms west has the grade and curvature of a pretty good roller coaster.

CDOT is just a far more power political entity than RTD.

I presume that State Department of Transportation authorities, Nationwide, are more powerful than their public transporation counterparts, also.

Most other nations have nothing comparable to the huge and powerful state highway organizations that 'blossomed' :rolleyes: during the Interstate highway boom. Instead, I suspect, in most other nations, the organizations that handle transportaiton have handled capital construction of all kinds for many decades- which gives such organizations the flexibility to implement new transportation strategies.

Germany uses 24 inch thick, steel reinforced concrete construction on their autobahns. The USA uses 8 to 12 inch asphalt or once in a while concrete (almost never steel reinforced concrete) on top of compacted dirt and/or shat base.

What?

My pavement design is rusty, but there are a few ways to design a concrete highway. One way does not include steel in the slab, that is true, although it would normally still include steel at the joints (different steel for transverse and longitudinal joints). We also do that same design with reinforcement in the slab, and then you can also design a road that is continuously reinforced. It just depends. But we "almost never use steel" is inaccurate.

Look, if there is any one thing you cannot say we as Americans don't so well, it's build highways. We've always done that well, too well, even.

The Germans may design things differently because they use different funding mechanisms and have different cost/maintenance approaches, etc... but that doesn't make it inherently better. Having higher upfront capital costs in exchange for lower ongoing maintenance costs is a policy decision, not necessarily a sign of one way being universally better than the other (apart from funding infrastructure generally, which they undoubtedly do a better...but we have a military that can pacify Libya with a finger snap; Germany, I'm not sure).

Oh, and Germany uses plenty of asphalt. In fact, at one point there was talk of the EU banning concrete highway construction. Not sure where it went, but it's indicative of very real downsides to concrete roadways. Noise being the most obvious area where asphalt is vastly superior (a smooth driving experience too).

I don't think we build our highways right. I'm talking about continuous steel rebar reinforced concrete poured to a thickness of 24 inches. This is what Germany does to construct their autobahns. As a result, they last 30 years, instead of 15 years. Not only that, they require less resurfacing and repair work during that 30 year life. The thicker and stronger slabs withstand the weight of heavy traffic, better. I don't believe US highways are constructed with more than a 12inch thickness. While rebar reinforcement is occasionally used in US highways, it certainly is not the norm.

So I'm just replying to Wizened, challenging the presumption that US highways are superior to what all other countries have. I honestly believe Germany has us beat in both highway construction and passenger rail.

I'm not questioning that Germany has higher quality infrastructure - both rail and to a lesser degree, highway - than the U.S. But your evidence supporting that is just flat wrong. I don't know where you got your info, but it's simply not true that all German highways use a continuously reinforced concrete section. And it's certainly not true that they uniformly use a 24-inch pavement section (that would just be stupid). And they make widespread use of asphalt.

The fact that they over-engineer their highways up-front and then require less maintenance is not what makes them superior.

The extraordinary O&M programs that the Germans use is what makes them superior. They have maintenance programs (and technologies) that make all but the most sophisticated U.S. highway departments/governments look downright obsolete. We've never been terribly good at maintenance, it's not how we think. Americans have always believed (and not just with roads) that you build something, and it's good until we need to re-build it. Our funding priorities reflect this.

So you are 180-degrees wrong in how you get to a correct conclusion. German roads are superior because of superior maintenance, not because of inherently superior design.

I have to think real hard, actually, to remember ever seeing a pothole on the autobahn, haha. Not sure I've ever seen one...

I would really hope the Autobahn gets more than 30 years if that much more effort is being expended into it. Though maybe the Autobahn has to be built stronger because of higher speeds.

I-215 (our I-15 belt loop in SLC) is almost 30 years old and still on its original concrete pavement. Overall it is in pretty good shape and I doubt they put the kind of effort into it that Germany does for their Autobahns.

For the 1-15 design build in Salt Lake County the entire road was repaved in concrete and the currently under construction 24 mile (5-6 lanes in each direction) design build I-15 CORE project in Utah County is being built with a concrete that is supposed to last for 40 years. It has a base of 12 inches of sand mixed with gravel, an additional 6 inches of drainage gravel, 3 inches of recycled asphalt from the old I-15 and 12-12.5 inches of portland cement concrete pavement.
http://youtu.be/p0itPSdstLQ

They said on a show on the Science Channel, Germany uses 24-inch thick rebar reinforced concrete on its autobahns, which is why they last so much longer than US interstates. The extra thickness and rebar prevents cracking, which is common on US concrete interstates. And the 30 year life was the minimum life expectancy, not maximum.

With the way US interstates handle large transports and more of them, I would think we would benefit from investing far more upfront, into constructing/reconstructing the interstate highways to last decades with minimal maintenance. a 24-inch thick, rebar reinforced concrete slab is going to last a very long time. I guess the real issue is with asphalt highways. I think the reason the US uses only 12-inch pours, is to cut costs and it leads to more potholes, cracks (and the maintenance costs associated thereof) and also private vehicular damage.

Perhaps it is the base preparation which is more important, than actual thickness? It just seems most the highways we build here, are doing good to last beyond 10years without major resurfacing work.

^I wonder if the Autobahn's robust construction is a leftover from the Cold War? A heavy duty construction meant to endure the movement of mechanized equipment and more resistant to indirect fire and air strikes.

The other interesting thing about the autobahn is how it influences automotive design. The autobahn tends to follow the natural contours of the land more than US highways. This adds distance, but distances in Germany are much shorter. There is also of course no speed limit. This explains a lot about why Germany and Italy are known for making high performance vehicles with great handling. US automobiles for many years had softer suspensions and less precise steering because on American roads this wasn't as important.

Strictly speaking, that's not true either. Only about two-thirds of German roads don't have speed limits. And that's rapidly changing too.

For example, the Green party-led government that just won in Baden Wuerttemberg (first state premiership ever held by the Greens...and an awfully odd place for them to start; the conservatives have held that state since the end of the war) has vowed to impose 75 mph speed limits on all roads. Yes, in Stuttgart, home of Mercedes and Porsche. And speed limits are expanding... and if the European Commission has its way, they'll become universal.

And it's not true, strictly speaking, that they follow the contours of the land more closely. You could argue that they follow them less, actually, because European roadway design uses grade separations more liberally than the U.S. does. Take the Millau Viaduct in southern France as a great example. A giant bridge over the Tarn River valley - you've all seen the pictures, if not, google it. That's how Europeans design roadways. In the U.S., the interstate would likely dip into that valley, cross the river on a short of a span as possible, and then climb back out. Greater environmental and traffic impacts, less capital cost. But strictly speaking, the U.S. road "follows the contours" more closely. I think the exact opposite of what you said is true (and is one factor that makes European roads better).

Man, you guys buy into all sorts of myths about Germany. The Science Channel, seriously? That's no different from Eeyore quoting Modern Marvels as the ultimate authority on the impact of the interstate system. If the Science Channel says that 24-inch continuously-reinforced concrete pavement is universal on the Autobahn, they're just flat out lying. Do you want me to post pictures of an asphalt road in Germany? I've only driven on a thousand of them. (I suppose they could be doing an asphalt overlay on a 24-inch concrete slab, but that'd be asinine.)

And yes, the condition of the subgrade is a huge part of their superiority. And like I said, maintenance. The reason you never see a crack on a German highway is not because their pavement never gets them. It's that they address them immediately through their awesome O&M programs.

What are you talking about? The US is very good at following the natural contours of the land. We're all about it! :d

http://farm4.static.flickr.com/3032/...82d18f00_b.jpg
source: telvsn on flickr

http://farm5.static.flickr.com/4119/...988d347c_b.jpg
source: he who shall on flickr

I really don't know anything about Germany. I just like that hill.

^^Tennessee?

And in Europe that would likely be a tunnel, rock structure allowing, of course. Unless it was built before the advent of strict environmental laws, in which case it would look exactly like that.

That big curve approaching it, however, would probably be straight, and there'd be a bridge over that little ravine.

Nice looking highway, actually.

I'm no geologist, but it looks like that hill was a volcano at some point. Glowy, please correct me if I'm wrong.

It's a giant fold in the earth from when North America and Africa slammed into each other millions of years ago. That's how the whole Appalachian range was formed (along with the Atlas Mountains in Africa, which are the same mountains).

If you click the "Maryland" link above and zoom out, you can see that it's not really a "hill" at all, but is a giant ridge extending for miles in both directions.

Thanks! I was just curious about that particular streak of white and red. With uplifting and folding of the crust, I would have expected the layers to go like this ////\\\\, rather than like this /\\_//\. It's not really a discussion for these forums, but I was just curious.

Thanks! That was very informative! This really brings me back to my Geology class at CU. It was fun going up every canyon west of Boulder and walking along the exposed layers back through time to when the Front Range was a shallow sea.