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[Plutonic Panda]

The latest news is not good:  Glenwood Canyon could be closed for weeks...or months.  And crew's can only do so much while rain (and associated risks) is in the forecast.

This site shows drone footage:  https://kdvr.com/news/local/gov-polis-update-on-i-70-damage-through-glenwood-canyon/

Workers are clearing the debris

https://www.denverpost.com/2021/08/06/glenwood-canyon-mudslides-i-70-cdot-photos/

[andy3175]

Federal funding is coming to help with the clean up.

https://www.thedenverchannel.com/news/local-news/usdot-approves-quick-disbursement-of-11-6m-for-glenwood-canyon-repairs-as-cdot-work-continues

Colorado’s request for a quick disbursement of $11.6 million in federal emergency relief funding was granted Tuesday by the Federal Highway Administration so work can continue to try to reopen I-70 through Glenwood Canyon as soon as possible. ...

The U.S. Department of Transportation said in a news release the $11.6 million would be used to reimburse the Colorado Department of Transportation for work it is doing to reopen Interstate 70 after clearing debris and assessing damage. They will also be used for the extra safety and patrols on the detours.
The USDOT and FHWA said additional funds the state requested this weekend “may be available later to continue repairs to I-70.” ...

The state officials said the federal funding would be critical to not only reopening one of Colorado’s most critical roadways and fixing the damage done by more than a dozen mudslides over the past six weeks, but also toward geohazard mitigation and a future resiliency and redundancy study for alternate routes, like Cottonwood Pass.

CDOT said while the current estimate was $116 million, it would provide a better assessment within 8-10 weeks. And those estimates could easily change if more mudslides occur. ...

CDOT said Tuesday afternoon that good weather has continued to help them in those efforts after hundreds of truckloads of material were hauled away from the canyon over the weekend.

Another 195 truckloads of debris were hauled away from the canyon on Monday as crews dug out culverts on the eastern side of the Canyon and continued to clear mud and other debris from the Blue Gulch area.

CDOT said they were able to dig down to three four-foot culverts that they are working on clearing out Tuesday, with the hopes to clear all the slides from Hanging Lake Tunnel to Bair Ranch on the eastbound side.

On the westbound side, crews are working Tuesday on uncovering a box culvert and building a pad where they will place 60 “super sacks” filled with sand on the north side of the road to help prevent future mudslides from bringing debris down again.

CDOT also said that its engineers believe one lane of westbound I-70 could reopen after material is cleared and more barriers and safety barriers are installed after reviewing the interstate’s infrastructure.

"This confirmation will help expedite the temporary westbound I-70 reopening timeline," CDOT said in the release.

Engineers said one lane of eastbound would be able to reopen once crews can reconstruct 100 feet of embankment and repave. Engineers will be doing additional inspections Tuesday at Blue Gulch, CDOT said. ...

Eagle and Garfield county commissioners discussed the future of Cottonwood Pass in meetings Tuesday, looking at six areas that could widen the road and make it safer, which would cost $10-15 million and could lead to closures at Blue Hill if that project is taken on, though officials still believe it could not be a permanent alternative to the interstate.

“We’ve heard nothing but good news so far today,” said Eagle County Commissioner Jeanne McQueeney. “CDOT’s statement that it will be days, not weeks, until I-70 could be reopened is amazing to hear. Clearly, reopening the highway would provide the most relief to this situation.”

SM-G975U

[andy3175]

Some recent developments on I-70 Glenwood Canyon:

https://kdvr.com/news/local/cdot-placing-car-sized-sandbags-to-protect-i-70-through-glenwood-canyon/amp/

https://www.cpr.org/2021/08/12/your-guide-to-the-i-70-shutdown-when-its-reopening-how-much-repairs-will-cost-and-why-it-keeps-happening/

https://www.cpr.org/2021/08/06/i-70s-extended-closure-at-glenwood-canyon-has-cdot-counties-eyeing-upgrades-to-a-nearby-alternative/

https://www.thedenverchannel.com/news/local-news/did-cdot-lie-internal-cdot-emails-show-why-employees-decided-to-misinform-drivers

[Rover_0]

On that last article: Classic Aspen NIMBYism?

[andy3175]

Interstate 70 reopened through the canyon this morning ...

https://www.9news.com/amp/article/weather/weather-colorado/cdot-i-70-re-opening-update-friday-afternoon/73-4bec34fc-b583-46b3-9140-2e5d451d22c5

One lane of Interstate 70 reopened each direction through Glenwood Canyon on Saturday morning, after nearly two weeks of cleanup due to mudslides.

The Colorado Department of Transportation (CDOT) gave that update on Twitter, saying the lanes reopened about 7 a.m. between Exit 116 in Glenwood Springs and Exit 133 in Dotsero.

SM-G975U

[stevashe]

On that last article: Classic Aspen NIMBYism?

Sounds like it was just not wanting large backups on Independence Pass, reading the article. It was an internal CDOT decision, not a result of outside pressure from any community.

[TheHighwayMan394]

On that last article: Classic Aspen NIMBYism?

Sounds like it was just not wanting large backups on Independence Pass, reading the article. It was an internal CDOT decision, not a result of outside pressure from any community.

It's more than that. Independence Pass is not suitable for trucks/trailers and would likely have created some potentially disastrous situations if that wasn't headed off quickly, as happened during the 2020 Glenwood Canyon closure.

https://www.summitdaily.com/news/glenwood-canyon-closure-has-truckers-trying-independence-pass-which-is-not-allowed-for-semis/

[stevashe]

On that last article: Classic Aspen NIMBYism?

Sounds like it was just not wanting large backups on Independence Pass, reading the article. It was an internal CDOT decision, not a result of outside pressure from any community.

It's more than that. Independence Pass is not suitable for trucks/trailers and would likely have created some potentially disastrous situations if that wasn't headed off quickly, as happened during the 2020 Glenwood Canyon closure.

https://www.summitdaily.com/news/glenwood-canyon-closure-has-truckers-trying-independence-pass-which-is-not-allowed-for-semis/

If that was the real concern then they should have just said so, and possibly set up a checkpoint to turn back trucks and trailers, not lied about the road being closed completely

[andy3175]

Updates... the route though Glenwood Canyon was closed for a portion of today due to a Flash Flood Warning:

https://www.9news.com/amp/article/weather/weather-colorado/i-70-at-glenwood-canyon-closed-due-to-flash-flooding/73-33d21574-ab68-4af5-91e1-a62b8ffe1b4e

  A Flash Flood Warning on Wednesday afternoon forced the automatic closure of Interstate 70 at Glenwood Canyon.

A slow-moving storm moved right through the flood-prone canyon on Wednesday, prompting yet another closure of the burn scar-affected stretch of highway. The National Weather Service issued the Warning for the area until 7:15 p.m. on Wednesday.

More storms could impact the area over tonight into Thursday thanks to a strong storm system moving through western Colorado. More rain is likely in Glenwood Canyon, meaning this could be an extended closure.

The Colorado Department of Transportation (CDOT) automatically closes the flood-prone stretch of highway anytime a Flash Flood Warning is issued by the National Weather Service. 

The Grizzly Creek burn scar is located right near the highway, and burn scars are especially vulnerable to flash flooding due to the lack of vegetation to absorb moisture. As a result, flood-driven mudslides are common near or even over the interstate.

And this article looks back at the most controversial sections of Interstate 70 - Sawnsea/Elyria and Glenwood Canyon.

https://www.westword.com/news/glenwood-canyon-interstate-70-construction-colorado-globeville-denver-12135326

Business dictated the location of many of Denver’s early transportation routes, including railroad lines. By 1880, dozens of railroad routes passed through Denver.

The railyards servicing those routes also attracted industry. Smelters were built along the lines in the communities of Globeville, Elyria and Swansea, small towns north of Denver that were later incorporated into the city. Globeville, which was established in 1889, became part of Denver in 1902, and the others soon followed.

“Globeville, of course, is named for the Globe Smelter, which was one of the largest smelters here,” explains Denver historian Tom Noel. “And so they moved down there along the Platte River, along the railroad tracks. There’s not much there but cheap worker housing. There was also the Swansea smelter, which gives its name to that neighborhood.”

Immigrants from Europe worked in the smelters. The Scandinavians were first, “then it switches to Poles, Slovaks, Eastern Europeans, Lithuanians, Latvians, Slavs, Slovenians,” Noel notes, adding that the smelter managers “liked to get a mix of groups so they couldn’t organize as easily, unionize as easily.”

In the 1940s, Denver officials and state highway planners started to mull the idea of establishing a major thoroughfare along 46th and 48th avenues. Back then, that strip of north Denver had the city’s worst traffic, and planners held a “belief that to be effective, highways must be placed where traffic was at its worst,” researcher Dianna Litvak wrote in her 2007 master’s thesis in history for the University of Colorado Denver, titled “Freeway Fighters in Denver, 1948-1975.”

By 1948, the route that would become I-25 was already cutting through the western portion of Globeville, and having a road head east from there made sense to planners, particularly since there was no strong political constituency in the area to argue otherwise.

In the late 1950s, federal highway planners added asphalt to injury when they suggested putting I-70 through this northern section of Denver, home to poor, working-class communities descended from immigrants. Local and state officials got to choose exactly where it would cut through the area.

“It was definitely built through a historically smelter community, so working-class people didn’t have the resources to complain or fight it,” says Lisa Schoch, a senior staff historian at CDOT.

“There was some protest from people, especially in Elyria-Swansea,” says William Philpott, a University of Denver history professor. “There was a citizens’ group there, and they tried to express concern that running this interstate through their neighborhood would turn it into a slum. They were especially concerned about this proposal to elevate the highway, elevate the freeway above street level. They felt that it would cut those neighborhoods north from the rest of the city.”

But despite opposition, plans went forward to have I-70 bisect the communities of Globeville, Elyria and Swansea, obliterating blocks of small houses and shops. “It seemed like there was no serious consideration of rooting that freeway anywhere else except for 46th,” Philpott says.

Possible alternatives, such as establishing I-70 farther north along 52nd and 54th avenues west of I-25 were scrapped because of higher estimated costs and the fact that a northern route would require even more displacement of residents. “This was a time when highway planners had tremendous power to dictate where highways would go,” Philpott explains.

A stretch of interstate through Denver completed in 1964 is now going underground.

In fact, what happened in Denver was occurring in urban areas across the country. “I-70 in Globeville really is a continuation of many such examples of neighborhoods with the least voice ending up being cut in half by the interstate,” says Paul Chinowsky, professor and director of the Environmental Design Program at the University of Colorado Boulder’s College of Engineering and Applied Science. “You see in cities across the country that it’s primarily the underrepresented areas, the poorer socio-economic areas, that ended up having the interstate go right through their neighborhood.”

The I-70 viaduct that spanned from Colorado Boulevard to I-25 opened in 1964.

By then, many of the descendants of the immigrants who’d worked in the smelters had left the area, which was becoming more heavily Hispanic. The newcomers to Globeville and the neighborhood that is now known as Elyria-Swansea inherited the legacy of those manufacturing days: The area is one of the most heavily polluted in the U.S.

While much of that contamination was remediated after the feds declared the area around Globeville a Superfund site, the highway didn’t move. In fact, after years of debate over how to expand I-70 in Denver — and whether to move it out of the city altogether — CDOT doubled down and decided to expand it along the original footprint but put a significant section underground.

Residents and activists pushed for government officials to “ditch the ditch” and move this section of I-70 so that the neighborhoods of Globeville and Elyria-Swansea could be reunited without having to suffer further adverse health impacts from increased traffic, dust, noise and various other construction impacts. Some local officials joined the fight, but they didn’t get very far.

“Unfortunately, those decisions that were made back in the 1950s are really difficult to undo,” says Chinowsky. “And it’s extremely costly when you try and undo that.”


In 2017, CDOT signed off on final approval to reconstruct part of I-70 in Denver, in what’s known as the Central 70 project.

In the meantime, construction was already beginning all around I-70 closer to I-25, where a massive expansion of the National Western Complex had gotten under way. Although neighbors had been brought into the planning process, they complained then — and complain today — that they will see few benefits from the $1 billion project.

As part of the Central 70 project, CDOT opted to remove much of the viaduct and lower I-70 between Brighton and Colorado boulevards while expanding the highway as it runs through Denver. The Central 70 project broke ground in 2018, and CDOT expects traffic to start flowing permanently through the new sections by late 2022. A park will be installed over the underground portion of the highway after that.

But while the park will at least partially reconnect the old neighborhoods, many residents don’t consider it much of a consolation prize. “It’s really the same old,” says Denver City Councilwoman Candi CdeBaca, a native of Swansea who represents the affected areas. “They kept the park just shy of the square footage that would have required ventilation. It wasn’t really ever about the neighborhood.

“The park is not some place I would want to send my kids to play, given what the pollution is going to be like — just given the size of the highway and the already polluted air in that area,” she adds.

Farther west along I-70, the problem is less about what I-70 does to its surroundings than what its surroundings could do to the interstate.

As railroads were being built across Denver, in the late 1880s the Denver and Rio Grande Railroad established a route through Glenwood Canyon, which had been carved out of the mountains eons before by the Colorado River.

“Here, the Colorado River has worked its way down through 1.4 billion years of limestone, dolomite, quartzite, granite, gneiss, and shale, cutting a narrow, winding gorge where multicolored cliffs and promontories rise high above the roaring waters,” Philpott wrote in his 2013 book Vacationland: Tourism and Environment in the Colorado High Country.

In 1902, fifteen years after the first train ran through the canyon into Glenwood Springs, construction wrapped up on the Taylor State Road, which also wound through Glenwood Canyon. At the time, the “threat of floods, rock slides, and snow earned Glenwood Canyon the reputation as one of the most dangerous routes for travelers in Colorado,” noted a historic analysis prepared by architectural and engineering firm Mead & Hunt for CDOT in 2019.

Thanks to a push from state officials, improvements were made to the Taylor State Road along Glenwood Canyon in the mid-1910s.

In the 1930s, Congressman Edward Taylor of Colorado argued in Congress for further improvements. In 1936, Taylor State Road became part of U.S. 24, an early highway that crossed much of the country, and two years later, Works Progress Administration employees, hired through the New Deal, blasted away more canyon walls and widened the highway. When it reopened in 1938, it was a joint segment of U.S. 24 and U.S. 6.

But although the Eisenhower administration envisioned connecting the entire country with the interstate highway system, I-70 was originally designed to stop in Denver.

"There was a long history of the main transcontinental routes not going through Colorado."
tweet this 

“There was a long history of the main transcontinental routes not going through Colorado,” says Philpott. The first transcontinental railroad skipped Colorado, instead going through Cheyenne and crossing the Continental Divide at a lower altitude; Denver boosters paid to get a spur line into the city. And the Lincoln Highway, which is now I-80, also skipped Colorado for Wyoming.

If I-70 had stopped in Denver, Colorado wouldn’t have become a major thoroughfare for travelers, and its capital might not have become a popular tourist attraction.

But Colorado officials weren’t willing to let their state be bypassed this time around.

Following intense lobbying by these officials that included a promise that Colorado engineers could create an all-weather route by building what later became known as the Eisenhower Tunnel, the feds acquiesced. In 1957, the Bureau of Public Roads gave the green light for an additional 500-plus miles of I-70 between Denver and Utah.

But there was more rough road ahead. Highway planners were looking at building I-70 through Glenwood Canyon, following parts of the existing highway system. But that decision led to intense battles between engineers and environmentalists.

In 1970, President Richard Nixon signed the National Environmental Policy Act into law, which required federal planners to conduct environmental reviews that included public and stakeholder input. By now, construction of I-70 was well under way and even finished in some stretches, but not the Glenwood Canyon area. Under NEPA, planners now needed to take human and natural elements into consideration.

In the early 1970s, highway planners weighed multiple options for the section of I-70 that had yet to be built in Eagle and Garfield counties. One was Glenwood Canyon. Another was building the highway through the Flat Tops Wilderness Area north of Glenwood Canyon, which would hit an elevation of over 10,000 feet and cross through a sensitive wilderness area, according to the Mead & Hunt analysis. Third on the list was following Cottonwood Pass southeast of Glenwood Springs, which would have required a 6 percent grade for over eight miles and also would have added 9.4 miles to the route.

Glenwood Canyon won out as the best option. “It was the most direct route, and highway planners love directness,” says Philpott.

[jakeroot]

Question about E-470:

I notice that most of the on and off ramp diamond interchanges have very long ramps. Much longer than most diamond interchanges. I've long been curious as to why.

The quick and easy explanation is that these ramps have toll collection facilities, which as far as I know have always been of the ETC-type (physical toll booths were always on the mainlines, not ramps -- I could very much be wrong there). But I don't see why the ramps need to be that long in order to facilitate tolling operations. Most of the ramp is just the ramp itself, and the tolling equipment is a small fraction of the overall length. If the section of the ramp with the toll collection facility has to be arrow straight, I can understand how that may increase the ramp lengths slightly. But from what I can see, the ramps still seem much longer than usual.

I suppose the other explanation is just that they wanted to make them long, to facilitate easier acceleration and deceleration.

Anyone else have any ideas?

Examples of what I'm talking about:

https://www.google.com/maps/@39.9840097,-105.018291,1481m/data=!3m1!1e3
https://www.google.com/maps/@39.9739582,-104.9371292,1245m/data=!3m1!1e3
https://www.google.com/maps/@39.813521,-104.7225466,1050m/data=!3m1!1e3

[i-215]

Most of the ramp is just the ramp itself, and the tolling equipment is a small fraction of the overall length. If the section of the ramp with the toll collection facility has to be arrow straight, I can understand how that may increase the ramp lengths slightly. But from what I can see, the ramps still seem much longer than usual.

I hadn't considered the toll road as part of the explanation.  But perhaps it was to accommodate the possibility of full-stop toll booths plus a healthy queue line.

Perhaps ETC was still relatively new in the 90s/00s when E470 was built, so maybe there was a fear Colorado might have to "go back" to the old form of toll collection.

[JayhawkCO]

Most of the ramp is just the ramp itself, and the tolling equipment is a small fraction of the overall length. If the section of the ramp with the toll collection facility has to be arrow straight, I can understand how that may increase the ramp lengths slightly. But from what I can see, the ramps still seem much longer than usual.

I hadn't considered the toll road as part of the explanation.  But perhaps it was to accommodate the possibility of full-stop toll booths plus a healthy queue line.

Perhaps ETC was still relatively new in the 90s/00s when E470 was built, so maybe there was a fear Colorado might have to "go back" to the old form of toll collection.

I think that's a fairly good guess.  When it was only open from I-25 to Parker Road in Parker, it was the first ETC in the country.  Maybe they weren't sure how well it would work.  I remember driving it back then and you'd maybe see 5-10 cars on the whole stretch.  It's still not busy now, but definitely getting busier.  Projections show that my town, Aurora, could double its population in the next 20 years because of housing developments along the highway.

Chris

[US 89]

Most of the ramp is just the ramp itself, and the tolling equipment is a small fraction of the overall length. If the section of the ramp with the toll collection facility has to be arrow straight, I can understand how that may increase the ramp lengths slightly. But from what I can see, the ramps still seem much longer than usual.

I hadn't considered the toll road as part of the explanation.  But perhaps it was to accommodate the possibility of full-stop toll booths plus a healthy queue line.

Perhaps ETC was still relatively new in the 90s/00s when E470 was built, so maybe there was a fear Colorado might have to "go back" to the old form of toll collection.

E-470 did in fact have cash toll collection once upon a time - with Oklahoma-style change baskets, even. Per this WSJ article it was only converted to AET with license plate tolls in 2009.

[thenetwork]

Another theory:  Way back when the idea of an Eastern bypass/beltway around Denver was first imagined, I believe they wanted the road to have speed limits posted around 80 MPH from day one (I want to say that's partly why they wanted this as a toll road -- they thought a private road could skirt the then-55 MPH limits).

Longer on/off ramps may have been built to safely support the higher speed limit potentials.

[jakeroot]

Most of the ramp is just the ramp itself, and the tolling equipment is a small fraction of the overall length. If the section of the ramp with the toll collection facility has to be arrow straight, I can understand how that may increase the ramp lengths slightly. But from what I can see, the ramps still seem much longer than usual.

I hadn't considered the toll road as part of the explanation.  But perhaps it was to accommodate the possibility of full-stop toll booths plus a healthy queue line.

Perhaps ETC was still relatively new in the 90s/00s when E470 was built, so maybe there was a fear Colorado might have to "go back" to the old form of toll collection.

E-470 did in fact have cash toll collection once upon a time - with Oklahoma-style change baskets, even. Per this WSJ article it was only converted to AET with license plate tolls in 2009.

In doing my initial research, it seemed that cash was only accepted at the mainline booths (such as here or here). I had originally thought the ramps were really long to keep traffic stopped on the ramps and not E-470 or any side-streets, but the ramps were, and always have been, ETC (i-215 and jayhawkco confirm this). So I did mention that in my original post as part of my confusion (ETC does not require stopping so there is no back-up concern).

The idea that toll booths could eventually be implemented seems plausible. But even then, these ramps are much longer than even those on and off ramps that do collect cash tolls elsewhere (Orlando area comes to mind).

Another theory:  Way back when the idea of an Eastern bypass/beltway around Denver was first imagined, I believe they wanted the road to have speed limits posted around 80 MPH from day one (I want to say that's partly why they wanted this as a toll road -- they thought a private road could skirt the then-55 MPH limits).

Longer on/off ramps may have been built to safely support the higher speed limit potentials.

I like this theory too. Has 80 ever come up as an option? I know it's 75 now.

[Elm]

Most of the ramp is just the ramp itself, and the tolling equipment is a small fraction of the overall length. If the section of the ramp with the toll collection facility has to be arrow straight, I can understand how that may increase the ramp lengths slightly. But from what I can see, the ramps still seem much longer than usual.

I hadn't considered the toll road as part of the explanation.  But perhaps it was to accommodate the possibility of full-stop toll booths plus a healthy queue line.

Perhaps ETC was still relatively new in the 90s/00s when E470 was built, so maybe there was a fear Colorado might have to "go back" to the old form of toll collection.

E-470 did in fact have cash toll collection once upon a time - with Oklahoma-style change baskets, even. Per this WSJ article it was only converted to AET with license plate tolls in 2009.

In doing my initial research, it seemed that cash was only accepted at the mainline booths (such as here or here). I had originally thought the ramps were really long to keep traffic stopped on the ramps and not E-470 or any side-streets, but the ramps were, and always have been, ETC (i-215 and jayhawkco confirm this). So I did mention that in my original post as part of my confusion (ETC does not require stopping so there is no back-up concern).

The idea that toll booths could eventually be implemented seems plausible. But even then, these ramps are much longer than even those on and off ramps that do collect cash tolls elsewhere (Orlando area comes to mind).

I don't have personal experience with these because of when/how I've used E-470, but it looks like there could've been unstaffed toll booths at the tolled ramps. Here's a photo from the old Colorado Highways site's E-470 photos page suggesting a cash toll at 104th Ave:


Attempting a StreetView link for 2009 at the southbound/westbound Chambers Road offramp, here, you can see a similar sign, and it looks like there's a collection basket on the booth.

(Don't know if an 80mph speed limit has come up, but for whatever it might suggest about the road's historical design speed, they posted advisory limits of 70 in some places when they raised the limit to 75, going by this article.)

[US 89]

Attempting a StreetView link for 2009 at the southbound/westbound Chambers Road offramp, here, you can see a similar sign, and it looks like there's a collection basket on the booth.

Looking at that booth even now, you can see where the coin basket used to be:

https://goo.gl/maps/5eKHbQcHKQ5oPHJ48

[jakeroot]

Great observations. It does seem that these toll booths were placed along the entire E-470, with the exception of the uncharacteristic partial cloverleaf in Parker.

The unmanned booths certainly makes things more interesting. It seems that perhaps some were just a single lane? That seems rather annoying for those who chose to use ETC. Perhaps that is indeed why the ramps are so long. Still not totally sold on it but it's a better explanation than "they felt like making the ramps long".

[thenetwork]

Most of the ramp is just the ramp itself, and the tolling equipment is a small fraction of the overall length. If the section of the ramp with the toll collection facility has to be arrow straight, I can understand how that may increase the ramp lengths slightly. But from what I can see, the ramps still seem much longer than usual.

I hadn't considered the toll road as part of the explanation.  But perhaps it was to accommodate the possibility of full-stop toll booths plus a healthy queue line.

Perhaps ETC was still relatively new in the 90s/00s when E470 was built, so maybe there was a fear Colorado might have to "go back" to the old form of toll collection.

E-470 did in fact have cash toll collection once upon a time - with Oklahoma-style change baskets, even. Per this WSJ article it was only converted to AET with license plate tolls in 2009.

In doing my initial research, it seemed that cash was only accepted at the mainline booths (such as here or here). I had originally thought the ramps were really long to keep traffic stopped on the ramps and not E-470 or any side-streets, but the ramps were, and always have been, ETC (i-215 and jayhawkco confirm this). So I did mention that in my original post as part of my confusion (ETC does not require stopping so there is no back-up concern).

The idea that toll booths could eventually be implemented seems plausible. But even then, these ramps are much longer than even those on and off ramps that do collect cash tolls elsewhere (Orlando area comes to mind).

Another theory:  Way back when the idea of an Eastern bypass/beltway around Denver was first imagined, I believe they wanted the road to have speed limits posted around 80 MPH from day one (I want to say that's partly why they wanted this as a toll road -- they thought a private road could skirt the then-55 MPH limits).

Longer on/off ramps may have been built to safely support the higher speed limit potentials.

I like this theory too. Has 80 ever come up as an option? I know it's 75 now.

Again, long long ago in the days of maximum 55 MPH speeds, I read a news article at the time saying some private entity was planning to build a limited access highway where people could go 80+ MPH.  I did take a college course in highways/highway designs in the mid-80s, that may be why I remember the article so well -- we might have discussed it in class.

[jakeroot]

Another theory:  Way back when the idea of an Eastern bypass/beltway around Denver was first imagined, I believe they wanted the road to have speed limits posted around 80 MPH from day one (I want to say that's partly why they wanted this as a toll road -- they thought a private road could skirt the then-55 MPH limits).

Longer on/off ramps may have been built to safely support the higher speed limit potentials.

I like this theory too. Has 80 ever come up as an option? I know it's 75 now.

Again, long long ago in the days of maximum 55 MPH speeds, I read a news article at the time saying some private entity was planning to build a limited access highway where people could go 80+ MPH.  I did take a college course in highways/highway designs in the mid-80s, that may be why I remember the article so well -- we might have discussed it in class.

No, I got that. Thank you again for the explanation. I was more curious if the idea of having an 80mph limit has come up again since construction. Given that it's 75 now, and Colorado is neighbored by a couple states utilizing 80, it doesn't seem like a stretch, especially as an attempt to continue encouraging more cars to use E-470.

[SkyPesos]

Was looking at CODOT's AADT tracker (which lists mileposts, and I really like that feature) and noticed something, is there a reason why US 24's mileage starts at 144, and CO 21 starts at 132, instead of starting at 0?

[thenetwork]

Was looking at CODOT's AADT tracker (which lists mileposts, and I really like that feature) and noticed something, is there a reason why US 24's mileage starts at 144, and CO 21 starts at 132, instead of starting at 0?

As for US-24, it used to duplex with US‐6 and I-70 all the way to Grand Junction and end at the junction with US-50. 

Once I-70 was officially completed in Colorado, US-24 was truncated to its current spot between Vail and Minturn. 

I guess it was easier to leave the mile markers be on what remains of US-24 than to renumber the highway all the way to Kansas. Likely when US-24 duplexed with US-6, it was following US-6's mile markers anyways.

[brad2971]

Was looking at CODOT's AADT tracker (which lists mileposts, and I really like that feature) and noticed something, is there a reason why US 24's mileage starts at 144, and CO 21 starts at 132, instead of starting at 0?

As for US-24, it used to duplex with US‐6 and I-70 all the way to Grand Junction and end at the junction with US-50. 

Once I-70 was officially completed in Colorado, US-24 was truncated to its current spot between Vail and Minturn. 

I guess it was easier to leave the mile markers be on what remains of US-24 than to renumber the highway all the way to Kansas. Likely when US-24 duplexed with US-6, it was following US-6's mile markers anyways.

Colorado DOT, frankly, is far from the only state DOT that does things like start highway mileage at a place other than zero. My native South Dakota, for example, has the entire length of SD Highway 262 and SD Highway 42 from 262 to Sioux Falls, in old US16's mileposts. Even though US16 hasn't been signed on those two roads since 1979.

[Elm]

CDOT is proposing a new rule for transportation projects, which would establish a "greenhouse gas transportation planning standard." CDOT's general proposed rule page is here, which includes the current draft, a link to the standard's webpage, and public comment information.

There doesn't seem to be much news coverage of it so far, but here are some reports, plus CDOT's release:

• CDOT: Colorado Developing New Pollution Reduction Planning Standards to Address Climate Change and Air Quality
  
• Colorado Public Radio: A Proposed Rule Would Target Colorado’s Polluting Road Projects
• Fox21News (Colorado Springs): Colorado Transportation Commission proposes new pollution and emissions standards
• Denver Business Journal (paywalled): Pollution-reduction plan could stop funding of certain Colorado highway expansion projects
  

From CDOT's release:

The draft standard would require CDOT and the state’s five Metropolitan Planning Organizations to determine the total pollution and greenhouse gas emission increase or decrease expected from future transportation projects and take steps to ensure that greenhouse gas emission levels do not exceed set reduction amounts. This approach will also streamline the planning and delivery of innovations that have proven successful in improving quality of life and air quality, like adding sidewalks, improving downtowns for active transportation with “complete streets,” improving local and intercity transit and first-and-last-mile connectivity to transit facilities, and adding bike-shares. This policy  recognizes that the transportation projects we build have an impact on how Coloradans travel and encourages choices for travelers across the state.

[Plutonic Panda]

So it will become harder to expand any roads or car based infrastructure in Colorado. Yet another tool those who have nothing better to do than sit around and sue. Great.