Description
I have called in to City of Roswell transportation dept leaving messages about this DANGEROUS intersection at Riverside Rd and Dogwood for South bound drivers turning left with zero results. I use the intersection several times a day and have observed numerous near collisions. Dogwood and Riverside going up to hwy 9 was repaived early 2019. Several months went by before it was striped. A left hand Turner sees there is a left arrow signal. When the light turns they assume they'll have the right of way. However, the oncoming traffic gets a green light and comes forward. That's when the near misses and horns blare. The stripe is too far back not allowing the waiting left hand turner to activate the sensor. When I'm first in line I move ahead 3/4 car length, which does not interfere with left hand turners coming off Riverside on to Riverside because it's protected by a cement island. When the light turns I always get a left hand arrow and the on coming cars don't move. City of Roswell Transportation, it's a simple fix. Black out the existing white line, move forward 3/4 car length, paint another white line. You can see the sensor strips embedded in the street. Sooner than later will be appreciated.
11 Comments
Department of Transportation (Registered User)
RDOT Admin 1 (Registered User)
RDOT Admin 1 (Registered User)
Acknowledged Traffic Engineering (Registered User)
Traffic Engineering (Registered User)
Scott Brunner (Registered User)
Scott Brunner (Registered User)
Good Afternoon,
Thank you for reporting your observations regarding the westbound-to-southbound left-turn operation at the intersection of Dogwood and Riverside. Roswell traffic engineering and signal operations staff observed the left-turning operation in the field and simultaneously observed the detector functions inside the cabinet. It was observed that most vehicles who were stopped in the left-turn lane, both somewhat in front of the stop bar as well as directly behind the stop bar triggered a call for a left-turn arrow. However, the detector signal coming into the cabinet was intermittent at times and was not detecting all vehicles that entered the left-turn lane, regardless of whether they were slightly in advance of, or directly behind the stop bar. In some instances multiple left-turners did not get the arrow. The circular green phase, however was always triggered.
As you noted, the intersection was paved some months ago, and the paving overlaid the original magnetic detector loops; and therefore the loops are in the same location they were before the repaving. Although the new WB stop bar was installed several feet further back from the old stop bar, about half of the loop should still be behind the new stop bar and detecting vehicles without issue. In fact, our vehicle was detected multiple times when stopped normally at the stop bar during today's testing. However, given the intermittent nature of the detection with cars in varying positions, we are going to thoroughly check the magnetic inductance of the loops, and troubleshoot the lead-in wires and other equipment for any latent issues that may have cropped up since the loops were overlaid. We suspect there is an equipment issue, and are not yet convinced simply moving the stop bar is the solution as a new loop may need to be installed.
In any event, we appreciate your follow-up on this, and we will notify you of our findings. Thanks for taking the time to contact us.
-Scott Brunner, City Traffic Engineer
sbrunner@roswellgov.com
DENNIS FITZGERALD (Registered User)
Scott Brunner (Registered User)
Scott Brunner (Registered User)
Here is the final disposition on this issue:
There were no issues found with the lead-in wires, in-road detector itself or the position of the loop relative to the stop bar, the loop is located where it will detect a vehicle in front of the stop bar and as well as behind it. However the detection for the subject left-turn loop has a 3-second delay programmed before it triggers, so therefore a vehicle (or group of closely spaced vehicles) must be stopped and remain present on the loop for about three seconds for the left-turn arrow to be called at the beginning of the next cycle. This is to make the overall operation of the intersection more efficient as most left-turns can clear without the arrow. Therefore, locking in a left-turn arrow call every time a vehicle passes over, or stops briefly on the left-turn loop is not necessary here. So, if you arrive and stop at the stop bar within the last couple seconds of the red phase, you will typically not get the green arrow because you were not there long enough to trigger the left-turn call from the controller (because of the delay setting).
We did opt to replace the existing loop signal detector in the cabinet with a version that is more somewhat more sensitive just to ensure that we had as much detection sensitivity as possible, but the heart of the issue is related to the programmed delay setting.
We will keep monitoring the situation out there, and leave this SeeClick Fix open for a few days longer. Thanks.
-Scott Brunner
Closed Scott Brunner (Registered User)
City staff will continue to monitor the operation at this intersection, but is going to close the SCF item for now.
-Scott Brunner