I received two separate, but similar letters about the roundabout on Pecos Street at I-70.
Cathy from Denver writes, “What's driving you crazy? The roundabout at Pecos/48th/I-70 is dangerous! The cars getting on near 48th do not yield, which makes it very difficult for cars coming off I-70 to get in the roundabout. I see a traffic light there in the future.”
Jeremy from Denver writes, “What's driving you crazy? The roundabouts at I-70 and Pecos. Every single time I drive west on W. 48th Avenue, people in the left lane for I-70 east will suddenly cut over to the right from inside the roundabout for the I-70 west ramp instead. People always seem to get confused at this roundabout since some parts are one lane and other parts of it are three lanes.”
I have received more complaints about these specific roundabouts than about all roundabouts in general. It is a unique design, with two roundabouts on either side of the Pecos Street bridge over I-70. Having 48th Avenue as part of the mix doesn't help driver confusion either. For many drivers, it is a tricky roundabout to work through.
The dual roundabout design was chosen for this area to smoothly move traffic on both sides of the new bridge, rolled into place eight years ago. You can read more about that process from the Wilson & Company Pecos Street page. There have been some improvements with the signage and striping of the roundabouts. Nearly three years ago, I covered the changes CDOT made to the northern Pecos roundabout to help with limited sightlines and better traffic flow. That helped somewhat but, according to the drivers who write to me about it, more needs to be done. People like Amanda in Denver who drive it every day tell me the layout and traffic flow isn’t smooth.
“I've seen a lot of almost accidents from people being in both lanes trying to get on 70 west. It's dangerous and driving me crazy!" she said.
Addressing your issue, Cathy, about drivers turning into the roundabout from 48th Avenue: After watching traffic flow through there, it seems part of the issue might be drivers coming off westbound I-70 aren’t yielding before going into the roundabout. Those drivers might be under the impression, since they are coming off a highway, that they have the right of way into the roundabout and don’t need to yield. Those drivers from westbound I-70 need to yield to the drivers already in the roundabout or slow down before heading in, which allows for drivers from 48th Avenue to get in. There are two yield signs on either side of the entrance to the roundabout off I-70 that tell the driver they need to slow and yield to the vehicles already in the roundabout. That should give the 48th Avenue drivers time to merge in. As for a traffic signal, that would require a total rebuild if the intersection away from the current roundabout and that isn’t likely.
As far as the three lanes issue, Jeremy, that is to accommodate traffic to or from 48th Avenue since the roundabout basically cuts right through it. There isn’t much that can be done to drop one of the lanes other than to eliminate the access from 48th all together and that would also require a total redesign of the intersection. There isn’t much chance of that in the long term. CDOT has made some adjustments in the past to improve safety and traffic flow and have plans for some more tweaks in the near future.
“We have taken a look at the location and have a work order to our markings crew to modify the striping within the roundabout,” says Bob Kiene, CDOT Region One Traffic Operations Engineer. “The major modification will consist of adjusting the lane alignment for the westbound 48th Avenue approach and adding a dotted ‘guide stripe’ to make it more clear that traffic bound for westbound I-70 needs to use the right-hand entry lane.”
CDOT hopes the new lines will help drivers steer clear of each other and stay in the proper lane because up to this point, drivers are running into each other too often in the roundabouts. I did a rough count of all the crashes that were reported to Denver police at both the northern and the southern roundabouts over the past five years. I tallied 246 in or around the north side roundabout and 85 crashes in or around the south side roundabout. That is a 3-to-1 difference in risk of a crash on the north side roundabout compared to the southern one.
All Denver police would tell me after asking if the roundabout, especially the northern one, is a trouble spot for them and what makes that area so crash prone is, “We encourage drivers to be courteous, pay attention and follow the rules when driving in roundabouts and on all roadways,” said Christine Downs with Denver police.
CDOT says they anticipate the work they will do on the new lane markers to be completed before summer as weather and temperature permit.