Andrew from Evergreen writes, “What is driving you crazy? Wondering why the cause of traffic back-ups (often for miles) on Sixth Avenue was not corrected when the Sheridan bridge/exchange was re-done a couple of years ago? Traffic comes to a stop eastbound every morning due to traffic merging onto sixth from Sheridan. The problem is the lack of a merge lane as the on-ramp/lane is extremely short (like 50 ft) and cars are still moving very slowly when they run out of space and have to merge. It would have been a simple thing to extend the lane as there is room to do so without encroaching in the wall that separates Sixth from the frontage road/neighborhood. It would not have been perfect, such as the long merge/exit lanes on I-25, but it could have been so much better. As it is congestion is horrible with huge back-ups every day and continues to worsen as our population explodes. Sixth is almost unusable in the mornings and the backs start at that Sheridan on/ramp every day. Help!”
Andrew, you perfectly identified the design flaw with the merge from Sheridan to join eastbound 6th Ave traffic. The old design is not up to day’s standards and is the reason for the daily slow traffic in from Lakewood. The ramp from Sheridan as it merges into the right lane on eastbound 6th Ave is only about 100 feet long. In comparison, the ramp from Federal to westbound Highway 36 is about four times that long.
The construction project you mentioned was an $11.5 million CDOT project that replaced the 6th Avenue bridge over Sheridan Boulevard. The original bridge was constructed in 1961 and was one of Colorado’s most deficient bridges. The new bridge was built to accommodate wider sidewalks under the bridge along Sheridan Boulevard and at the four pedestrian islands. The medians north and south of the bridge were also modified to increase left turn storage capacity which will help with the flow of traffic on Sheridan Boulevard. The new bridge construction was finished in the summer of 2013.
Much of the funding for that bridge replacement came from the Colorado Bridge Enterprise Fund. That fund uses a small portion of vehicle registration fees to repair or replace poor bridges. CDOT says because this was a bridge replacement project, there wasn’t additional money to improve the flow of traffic to or from 6th Ave, including extending the ramp from Sheridan to eastbound 6th Ave.
While it looks like CDOT could just rework the right shoulder area to extend the ramp another 100 feet, there are certain guidelines they have to follow before any work can be done. The guidelines set for the length of highway ramps is found in the Manual on Uniform Traffic Control Devices for Streets and Highways. It would recommend a much longer ramp, however, CDOT says they don’t have the money or the room to build a longer ramp.
“The right of way is very constrained at this particular location and any attempt to have extended or expanded an auxiliary merge lane at that time would have resulted in right of way acquisition,” said CDOT’s Stacia Sellers. “That would include significantly greater costs due to the utilities, environmental clearance efforts and cost due to the very close proximity of the adjacent homes.”
The other major design challenge for CDOT are not only the homes next to 6th Ave but the location of the frontage road and sound walls that abut up to 6th Ave. As it was explained to me by a former project engineer, in order to make room for the extended ramp, the frontage road would most likely be cut off at Wolff Street. A few homes might have to be purchased as part of eminent domain. That additional space could then be turned into a longer ramp separated by large sound wall barriers right up next to the highway and homes that remain on the south side of 6th Ave.
CDOT acknowledges this is a problem area and would like to fix the interchange, bringing it up to current design standards. However, as with most of the improvement projects needed around the state, CDOT does not have any money to make the necessary improvements at this time. My experience there is that the left lane moves a touch faster past Sheridan than the center or the right lane but then you are faced with the difficult challenge of merging over two lanes if you want to get to I-25. CDOT doesn’t have any time frame when they could make any of the improvements they would like to improve the traffic flow on eastbound 6th Ave.
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