C.J. from Denver writes, “What's driving you crazy? What is up with the new odd lane striping on Downing St. at Mexico Ave? It is forcing traffic into the parking lane. I saw a truck almost hit a parked car trying to stay in the new lane that was created.”
You had me at odd lane striping, C.J. That I had to see for myself. When I drove down S Downing Street, south of Interstate 25, and approached Mexico Avenue, how I can best describe what happens now is that the double yellow center line splits into the letter Y. One Y before Mexico Avenue and another Y on the other side of Mexico.
The right side of the double yellow Y is supposed to force you to drift right. Then, there is a gap in the paint where traffic from Mexico Avenue would cross Downing. Then, there is the same letter Y center line layout again that starts as a split but joins together back into one regular double yellow line. It is the first time I have seen the yellow center line split in this way.
This center line split is a fairly new traffic treatment for the City of Denver. It is used only in two other places in the city — both are along Julian Street on the west side of town. One is at 23rd Ave. The other is at 29th Ave.
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I went to Denver’s Department of Transportation and Infrastructure to ask about this change to the center line. When I spoke with Nancy Kuhn, DOTI’s director, she told me that the new center line split is a first step to change the look of that section of S Downing Street with the goal of slowing drivers down.
Denver traffic engineers told me, the new striping is intended to create a slight deflection to the right, which has been shown to slow traffic down. They said the deflection hinders the ability of a person to drive in a straight line, so they naturally slow down to comfortably navigate the roadway. The marking gives the visual impression that the width of the roadway has been reduced, which has also been shown to slow vehicles down. I saw something similar in Ireland. Not at an intersection, but in random spots along long stretches of open road where there was a small median built in the middle of the roadway, designed to narrow the lanes and slow down traffic.
Narrowing travel lanes, whether by impression or physically, is one method of something called traffic calming — a system of helping to naturally reduce driver’s speed. Other popular traffic calming devices are speed humps, chicanes, traffic circles and bulb-outs. All of these techniques e ither reduce the size of a travel lane or make the lane feel narrower, which makes drivers want to slow down.
Canada’s SMATS Traffic Solutions explains other ways that lane narrowing can be accomplished through widening of sidewalks, creating bicycle lanes, landscaping or inserting raised medians in the center of the roadway.
“Narrow lanes encourage driver alertness, and cause motorists to slow down in order to increase driving comfort,” Canada’s SMATS Traffic Solutions said.
While I was watching traffic flow through the new center line split on South Downing Street, I saw most drivers never slowed down. They ignored the lane split to the right and kept going straight, driving right over the yellow lines that were designed to push them to the right and get them to slow down. The few drivers that did weave right, then back left slowed very slightly, and came very close to the vehicles that were parked at the very end of that parking lane. Kuhn told me, if a driver goes the speed limit, or slower, they should have no trouble navigating the closeness of the parking lane. The problem, according to DOTI, is that drivers are still going to fast.
“Our speed collection data on Downing showed that 85% of drivers are operating at or below 37 miles an hour. It’s only signed at 30 miles per hour, so going 37 is certainly going to make crossing the stretch on foot more uncomfortable. 15% of drivers are exceeding 37 miles per hour,” Kuhn said.
I asked the city about adding a crosswalk to further slow down traffic. Kuhn told me, a crosswalk would not be a safe idea to add here.
“It would not be safe without also adding a signal of some sort to stop drivers. We don’t currently have funding for a new signal identified, so in the meantime, we’re exploring additional treatments to slow drivers down,” Kuhn said.
The city said, workers will be out watching how traffic flows along Downing at Mexico and elsewhere in the area to see if the lane split intervention has helped to slow traffic. They view this as a trial and error process, exploring and trying more techniques to slow down speeding drivers.
“The yellow markings on Downing are a first step and we’re likely looking at an iterative process, exploring/trying more things, as we don’t have funding identified yet for a signal/rapid flashing beacon that could help stop traffic and allow people to cross on foot,” Kuhn said. “As we continue to further refine the corridor improvements, we will be adding more calming elements.”
Denver7 Traffic Expert Jayson Luber says he has been covering Denver-metro traffic since Ben-Hur was driving a chariot. (We believe the actual number is over 25 years.) He's obsessed with letting viewers know what's happening on their drive and the best way to avoid the problems that spring up. Follow him on Facebook, Twitter or Instagram or listen to his award winning Driving You Crazy podcast on any podcast app including iTunes, iHeartRadio, Spotify, Podbean, or YouTube.
