Future changes to Aspen roundabout on city’s shoulders
If any significant changes are made to the Aspen roundabout, the lion’s share of costs will be the responsibility of the city government, according to the Colorado Department of Transportation.
Andrew Knapp, CDOT’s resident engineer who is assigned to Highway 82, said the state agency had planned to do an “asphalt mill and fill” project in the traffic circle in 2022.
But city engineers expressed a desire to put a concrete surface around it to prevent massive potholes, which occurred this past winter when traffic was at its heaviest.
That big blowout is what started the conversation between CDOT and the city, Knapp said.
“We had a basic surface project but now with this partnership, the city would reconstruct the surface with concrete and we are going to contribute what it would cost for the asphalt,” he said. “There will be no change to the geometry and lanes.”
The city is considering a $100,000 consultant study on traffic patterns surrounding the roundabout in advance of the work in 2022.
Engineers would be looking at ways to improve traffic circulation in what is one of the busiest roundabouts in the state.
CDOT rates it a “D” in level of service (LOS), which is defined as the relationship between roadway volume and roadway capacity, according to Pete Rice with the city’s engineering office.
“LOS D is defined as lanes being almost full with delay,” Rice wrote in an email. “We had a presentation once from a traffic engineer working on a traffic impact study on Maroon Creek Road who stated the roundabout congestion could be considered an F, but … we don’t have the data to prove anything and CDOT considers the corridor a D.”
The traffic study would provide that data, which could lead to improvements such as roundabout metering signals that would alternate cars entering the traffic circle from Maroon and Castle creeks.
Changes like that would entirely be up to the city, Knapp said, acknowledging that CDOT is underfunded.
And the idea is that whatever changes would occur, they would be done when the surface work is happening.
Aspen’s roundabout was built in 2001 when the concept was fairly new to traffic engineers.
“If we had to do it all over again, we would have done it differently,” Knapp said, adding that the Aspen roundabout was uniquely designed with a crown so the inside lane drains into the center and the outside lane drains away from the circle.
Carbondale’s roundabout is one of the newest designed and built, and serves as a good example of how a traffic circle should function, Knapp said.
There is just one circulating lane, and it is wide and defined for motorists entering it, he added.
CDOT just repainted Aspen’s roundabout to give motorists more direction on how to exit the circle.
That’s because drivers are hesitant to move into the outside lane for fear that those entering from the west will cut them off or hit them so they stay in the inside lane until it is time to exit.
A solid yellow line now delineates two lanes, with dotted lines painted coming off the inside one to signal motorists to move into the outside lane if they are planning to exit onto Maroon Creek or Castle Creek roads.
“We put the well-thought-about repainted lines in there,” Knapp said. “The median spiral pushes you to the outside and is meant to reduce the conflicts between the exiting traffic and the entering traffic.”
Also on CDOT’s agenda for Highway 82 is resurfacing the road in Snowmass Canyon.
Knapp said he was able to get that project, which was on CDOT’s 10-year plan, on the short list for 2023.
“That has been a big priority for me,” he said. “I consider that a big win.”
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