Jeananne from Henderson writes, “What’s driving you crazy? I have a question at E 120th Ave at Moline Street. Why is there a no turn sign saying you can’t turn left?”
I’m told it is all about a safe sight distance. More on that in a moment. I spent about two hours watching traffic at that intersection Jeananne and during that time I saw more than half of the drivers coming out of the Still Water neighborhood make the left turn anyway.
That intersection is maintained and managed by Commerce City. I talked to their public works department who tells me the original 2001 traffic study stated that there was a concern about the limited sight distance for left turning drivers. The problem is when drivers look right, or east toward the traffic that is coming west on 120th Ave., there several large trees and other vegetation in front of a private home that obscure the view of drivers enough to where they can’t see when it is safe to pull out and head west. The traffic study also stated since there isn’t a city right-of-way on the south side of 120th, the city has no authority to remove the vegetation. That is why the no left turn was installed because of the difficulty drivers have seeing far enough down the road and then trying to pull out blind and join the traffic safely they can’t see coming.
Conversely, there isn’t the same sight distance issue from Oakland Street two blocks away. Looking east down 120th Ave. from there is a clear view so that is why the left turn is allowed giving the Still Water residents an easy alternate to go west on 120th. The third, and city's preferred option, is to use 119th Ave. from the Still Water neighborhood and make a left on Peoria to get to the traffic light where drivers can safely make the left onto westbound 120th. Commerce City traffic engineers say this route is the safest nearby option for residents to go west on 120th.
I also spoke with Adams County Public Works. While they don’t manage these intersections, they still weighed in, telling me that left-turn restrictions are often placed at intersections where there is a concern for driver safety due to limited sight distance, the number of points of potential impact between two vehicles created by allowing the movement, a history of broadside crashes that might be mitigated by the no left-turn restriction or a small available gap-selection during peak traffic periods. In other words, is there enough time and distance between approaching vehicles to make a left turn safely?
I asked the city if they would reconsider the prohibited left or would install a traffic signal at Moline. I was told, “the city does not currently have plans to add a traffic signal at either Moline or Oakland but would reevaluate that based on future development and/or 120th Avenue roadway improvements.”
The Commerce City Police Department tells me if they see someone making that illegal left turn they could write that driver a citation for “left turn from/onto street when prohibited”. It's a four-point offense with a fine of $80, but depending on a driver’s history, if you appear in court, whether there is an accident, etc., the total cost including court fees could total upwards of over $200.
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 Driving You Crazy podcast on iTunes, Stitcher, iHeartRadio, Spotify or Podbean.