Post Number: 1
|Posted on Saturday, April 25, 2009 - 10:05 am: |
Can you please explain why the 2nd right turn lane at this corner changes to "east bound / straight ahead only" after rush hour each day? Based on how traffic stacks up to head south on the parkway after rush hour while this lane basically remains empty, it seems the more efficient option would just be to have this lane remain open at all times to vehicles wishing to go either east or south. Is it a safety concern of some kind? Thanks.
Joel Fitts, Senior Traffic Engineer
Post Number: 35
|Posted on Tuesday, April 28, 2009 - 12:27 am: |
The changeable lane assignment sign was installed to dynamically serve the different traffic patterns that occur at that intersection. Initially, two dedicated right-turn lanes were permanently marked, which served the morning rush hour traffic well. However, the sole remaining through lane was not enough to serve eastbound traffic at other times of the day (while the second right-turn lane remained empty). Consideration was given to a lane that always allowed through and right-turn traffic as you suggest; however, just a few through vehicles in that lane in the morning could block the entry point to the right-most right-turn lane, which would cripple its ability to allow traffic to turn right-on-red.
Therefore, the changeable lane assingment sign was installed so that the operation of the lane could change based on the different demand for right-turning traffic and through traffic at different times of the day. At the time, we could not locate an electronic sign that displayed the right only, through only, and through-and-right images. And so we were limited to providing either right only or through only.
As recently as a couple months ago, we counted the traffic movements on the eastbound approach to this intersection over the course of the day and still found the need to switch from two right-turn lanes to two through lanes. However, we determined that the two right-turn lane mode needed to stay on for a longer amount of time in the morning.
We will continue to periodically check the traffic demand for these different movements to determine if the operation of the changeable sign needs to be adjusted. In the long term, when more funding is available, perhaps we can locate a new electronic sign that gives us the ability to provide the shared-use lane mode. However, we cannot justify replacing this equipment at this time because our limited funding is currently prioritized for other roadway improvements needed at other locations (for traffic signal installations or roadway widening).
Senior Traffic Engineer