Highest and Lowest Interstate

[Chris]

I always wondered why American Interstates are much higher in altitude than in Europe, considering the Alps are about the same height as the Rocky Mountains (although on a much smaller scale ofcourse).

The highest in the Alps are around 4,200 feet (Brennerpass I think). Some Spanish freeways are a bit higher, tipping 4,600 feet.

Maybe Alpine valleys are lower, and allow a freeway to pass at lower altitudes. Perhaps it's also because we tend to have somewhat more/longer tunnels. The Gotthard tunnel in Switzerland is 10 miles long and replaces a 7,800 feet mountain pass above it.

The highest freeway-grade roads are in Bolivia, I noticed some La Paz freeway-like roads are at 13,000+ feet.

[Duke87]

I always wondered why American Interstates are much higher in altitude than in Europe, considering the Alps are about the same height as the Rocky Mountains (although on a much smaller scale ofcourse).

The highest in the Alps are around 4,200 feet (Brennerpass I think). Some Spanish freeways are a bit higher, tipping 4,600 feet.

Maybe Alpine valleys are lower, and allow a freeway to pass at lower altitudes. Perhaps it's also because we tend to have somewhat more/longer tunnels. The Gotthard tunnel in Switzerland is 10 miles long and replaces a 7,800 feet mountain pass above it.

Consider the surrounding geography. Denver is already at 5280 feet, so the Eisenhower Tunnel is really only about 6000 feet above the baseline of the mountains.

This applies elsewhere, too. The Rockies are quite on the interior of the continent, whereas the Alps are, in general, much closer to the sea. This makes a climb equally high into the Alps much steeper, which would make altitude sickness a problem if the roads got too high. I've been to Rock Mountain National Park. I can tell you what 12000 feet feels like. You get short of breath very easily. And that was after having been up in the mountains for a few days. Someone who flew into Denver in the morning from someplace like New York and then drove directly up Trail Ridge Road to the top would likely collapse from lack of oxygen.

Finally, you have to consider the weather. The Eisenhower Tunnel isn't even quite above the treeline. Something that high in the Alps would be above the snowline, perpetually covered in ice and snowdrifts year round.

[Scott5114]

Wonder what they are in Kansas?

The highest point in Kansas is Mount Sunflower, is a couple dozen miles south of I-70 at Kanorado.

[DrZoidberg]

Would I-75 Alligator Alley constitute a low point?

[corco]

The lowest interstate in Washington is almost certainly I-5 where it gets down towards Kelso- that's basically sea level right there.

The highest Interstate point in Wyoming and along I-80 is at Elevation 8640 by the WYO 210/Happy Jack Road interchange between Laramie and Cheyenne

[TheHighwayMan3561]

I would guess in Minnesota the highest is I-35 coming into Duluth. The Sawtooth "Mountains" are the highest points of land in Minnesota and run along the North Shore, and I-35 crosses over one of them, Thompson Hill, on the way into Duluth.

Lowest: Also I-35 in Duluth maybe!!...Lake Superior's shoreline is the lowest point in Minnesota. I-35 comes within a couple hundred feet of the lake on the way to its terminus. Either that or I would say I-90 or I-94 in the western part of the state where the plains start.

[Voyager]

What about Florida? 

[Urban Prairie Schooner]

Wouldn't be surprised if I-10's lowest point nationally was this location:

http://www.southeastroads.com/louisiana001/i-010_wb_exit_231b_03.jpg

The Railroad Underpass of Doom - Likely the lowest point in a city which itself is about 50% below sea level.

So low in elevation and so flood prone, the S&WB built a massive pumping station especially to drain the location (the square tan structure visible in the background).

[SSOWorld]

Highest in WI has to be near Baldwin (near Eau Clare) on I-94
Lowest - I-43 in Green Bay

[renegade]

... The Rockies are quite on the interior of the continent, whereas the Alps are, in general, much closer to the sea. This makes a climb equally high into the Alps much steeper, which would make altitude sickness a problem if the roads got too high. I've been to Rock Mountain National Park. I can tell you what 12000 feet feels like. You get short of breath very easily. And that was after having been up in the mountains for a few days. Someone who flew into Denver in the morning from someplace like New York and then drove directly up Trail Ridge Road to the top would likely collapse from lack of oxygen.

This was me.   i flew to Denver from Detroit.  As soon as I was in the rental, I was on my way to Mount Evans, elevation 14,280 feet, a difference of 13,780 feet in just over four hours.  The air was so thin it was a five-minute walk from the driver's seat to the trunk.   

[amroad17]

I-80 in PA is higher than I-93 in Northern New Hampshire or I-91 in Northern Vermont?

Poking around Google Earth indicates:

- I-87 getting upt to 1300 feet or so at a couple spots in the Adirondacks, but that's it.
- I-89 peaking at about 1700 feet south of Northfield, VT
- I-91 peaking at about 1900 feet north of Sheffield, VT
- I-93 peaking just shy of 2000 feet in Franconia Notch
- NY-17/I-86 peaking just above 2100 feet west of Karrdale

So that neck of the woods doesn't beat I-80.

However, I-64 gets up to about 2450 feet at the VA/WV line, so we can prove by counterexample that I-80 there is not the highest point on any interstate east of the Mississippi.

As to whether that one on I-64 is the highest... I don't know. I'm not running my mouse pointer along every interstate in the Appalcacians.

I-64 gets up to near 2800' at the top of Sandstone east of Beckley, WV.  I believe I-77 at Flat Top south of Beckley is around 3200'.

[Road Hog]

Highest one in Texas is probably I-10 east of El Paso through the mountains in the Van Horn area. Although I-40 in the Panhandle is above 4,000 feet as well at the New Mexico border. No mountains, just high, flat plains.

Lowest is either I-45 at Galveston or I-37 at Corpus Christi (basically sea level). I-2 doesn't quite make it all the way to the Gulf.

[Thing 342]

Virginia:
Highest: 64 at the Va/Wv border.

Lowest: One of the tunnels in Hampton Roads, most likely.

[bassoon1986]

Wouldn't be surprised if I-10's lowest point nationally was this location:

http://www.southeastroads.com/louisiana001/i-010_wb_exit_231b_03.jpg

The Railroad Underpass of Doom - Likely the lowest point in a city which itself is about 50% below sea level.

So low in elevation and so flood prone, the S&WB built a massive pumping station especially to drain the location (the square tan structure visible in the background).

And I'd wager that the highest point would be on I-20 in Bienville parish somewhere. It's the hilliest section and not far from Mt. Driskill

[roadman65]

I know that I-95's lowest point is probably the Fort McHenry Tunnel in Baltimore, but trying to find its highest point is hard being most of the road is the low lying coastal ranges it entire route.

Perhaps, it would most likely be in Maine as I am assuming that Appalachians due cross the path of I-95 there somewhere north of Augusta or maybe Bangor.  I have not been up there ever, so I cannot have seen how the road is there.

I-4 is probably the most toughest as the whole elevation of Florida is less than 1000 feet.  You do not see much action on I-4 as far as hill climbing its entire run, and the land seems relativity flat .  I could not tell either point with this interstate.

I-75 on the other hand you could guess that its southern terminus is the lowest, being close to Miami, and the mountain range just south of the KY-TN state line is the highest.  However, just because you climb to get someplace does not mean you are at the highest either as we have many high points even on flat ground.  Look at Dodge City, KS being higher in elevation that many peaks on the Appalachians.  Dodge too is on flat ground, but the land of the continent has a slow upward slope west of the Mississippi River into the Rockies that causes that.  Therefore the climb to get to Dodge is not at all noticeable, so maybe a GA may have higher places along the route that does not require drastic climbs.

[The High Plains Traveler]

Another way of looking at this question is the longest continuous stretch of interstate above whatever threshold you consider to be "high altitude". If you pick 3000 feet, for east-west routes it's likely I-40, which is above that elevation continuously from west of Kingman AZ to east of Amarillo TX. I would guess that distance to be in the neighborhood of 700 miles. I-70 might come close to that, since you cross the 3000 foot contour somewhere east of Oakley KS. And, it just occurred to me that all of I-25 is likely above that elevation, so that would make it the longest overall route, at about 1050 miles. This isn't as significant a measurement, since I-25 basically follows the Rockies, so it is by virtue of its location at a higher elevation.

[Mapmikey]

Virginia:
Highest: 64 at the Va/Wv border.

Lowest: One of the tunnels in Hampton Roads, most likely.

I-77 reaches about 3000 ft just south of the Walker Tunnel...

Mapmikey

[NWI_Irish96]

I don't have Google Earth so I can't be very precise, but for Indiana the lowest would be near the 5.2 mile mark of I-69/164 in Evansville.

Highest would be near the 152 mile mark of I-70 near Richmond.

[texaskdog]

Highest point in the Nation?  I-70 (Eisenhower Tunnel in Colorado)

Lowest point in the Nation? My guess is I-8 in the Imperial Valley, California.

Yeah this is probably it

[NE2]

Damn Nimbyans for canceling I-420.

[getemngo]

I would guess in Minnesota the highest is I-35 coming into Duluth. The Sawtooth "Mountains" are the highest points of land in Minnesota and run along the North Shore, and I-35 crosses over one of them, Thompson Hill, on the way into Duluth.

Lowest: Also I-35 in Duluth maybe!!...Lake Superior's shoreline is the lowest point in Minnesota. I-35 comes within a couple hundred feet of the lake on the way to its terminus. Either that or I would say I-90 or I-94 in the western part of the state where the plains start.

Actually, you've got the highest point backwards. It doesn't look like I-35 around Duluth gets higher than about 1300'. Exit 249, Boundary Ave, is 1191'. Impressive when that's 700 feet above the lake, but I-94 reaches 1416' at the rest area near Alexandria. I-90 is actually above 1400' at the South Dakota state line and seems to top out at just over 1700' west of Worthington.

This seems to be true of most states: the flat points far away from the coast (or biggest river, or whatever) are higher than the "mountains" near it. Not always, since Eagle Mountain is right by Lake Superior, but in general it makes highpointing nice and boring.

[triplemultiplex]

Highest in WI has to be near Baldwin (near Eau Clare) on I-94
Lowest - I-43 in Green Bay

If I-39 ever found its way further north, it would eclipse that by a couple hundred feet around Brokaw.

Specifically, the lowest point on I-43 would be right around its northern terminus at US 41 as it crosses the Duck Creek Estuary.
The addition of I-41 will not result in a 'tie' since I-41 will end at I-43 and crosses over it at that point.
The coming reconstruction of this future double I-terminus will also not change this.

[ap70621]

Not sure about New Jersey. If I was to guess the highest would probably be somewhere in the western part along I-78 or I-80. The lowest would probably also be I-78 in the Holland Tunnel.

[cpzilliacus]

I know that I-95's lowest point is probably the Fort McHenry Tunnel in Baltimore, but trying to find its highest point is hard being most of the road is the low lying coastal ranges it entire route.

Perhaps, it would most likely be in Maine as I am assuming that Appalachians due cross the path of I-95 there somewhere north of Augusta or maybe Bangor.  I have not been up there ever, so I cannot have seen how the road is there.

I-95 between Bangor and Houlton is remarkably flat.  It is possible to see Mount Katahdin to the west of the freeway in Baxter State Park, but the mountain "stands alone" around relatively flat (never close to 1,000 feet above sea level) and mostly forested lands.

[Alps]

Not sure about New Jersey. If I was to guess the highest would probably be somewhere in the western part along I-78 or I-80. The lowest would probably also be I-78 in the Holland Tunnel.

Another highest possibility would be I-287 in the north. I tried checking, but:
* Google Maps is stuck in Preview mode, which doesn't show Terrain lines dark enough or at the necessary zoom level
* Acme maps re-centers the page every time I try to zoom in on the Topo
* I am too impatient to keep trying