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Letter To The Editor: Current Council Should Reconsider Previous Request For Roundabout At Central

on February 4, 2016 - 10:54am
Los Alamos
I second Tony Amsden's call ( ) for the County and State DOT to have a signal installed at Central-Trinity-N.M. 502 now that NMDOT has delayed its construction until 2017.
A traffic signal was NMDOT's choice over a roundabout when they first addressed the roadway over a decade ago. NMDOT acquiesced to LAC when council chair Rogers and vice-chair Izraelevitz visited them 3-years ago in SF to convey council's wishes for a roundabout. 

A traffic signal is consistent with all of the other controls on NM502. It allows "timing" and lane controls that are not available in a roundabout scheme. Once installed, a roundabout is literally set in concrete. 

Consider these factors:
  • A signal allows emergency vehicles to move rapidly through the "intersection" unabated as they can "operate" the signal. 
  • As currently designed, but not as originally presented, the roundabout has no slip lane to facilitate flow out of town in the evening. "Uninhibited" flow eastward was one of the main features that the NMDOT wanted in a redo of the highway to 2-lanes eastbound. With a signal, the outer east-bound lane can be set to be always "green" during evening rush hour. In contrast, all traffic, in any direction, must pause before entering the roundabout eastbound. 
  • Similarly, to the evening rush hour, all traffic must pause before entering the roundabout moving westward. A signal can be adjusted to make the flow smooth. 
  • With a signal at Smith's, a coordinated signal at Central-Trinity-502 makes much more sense than a roundabout that can not be altered as flows would dictate. 
  • Allen Cogbill ( ) has expressed concern about truck traffic on Central. The currently designed roundabout will actually facilitates westbound flow into Central.
In addition to these considerations, I recommend that 2 westbound thru lanes pass thru this intersection to properly mesh with the 2 westbound thru lanes that already exist on Trinity next to Smiths. (Actually, Trinity at this point has 2 westbound lanes and a turning bay for Smiths.) The current flow of a single lane into them with the left-turn lane into Smiths is NOT smooth. (The left-turn bay into Smiths is another piece of the puzzle that now shows the need to modify the planned design before NMDOT gets going on it). 

If the current LAC council persists in calling for a roundabout at Central-NM502, in spite of the advantages of a signal, it should still ask for 2 westbound lanes as I have indicated from Central westward. The current roundabout design is a 2-lane roundabout with all of the outside westbound lane flowing to Central. The flow into Central should be a standard roundabout split of the outside westbound lane for Central with the primary continuing through to the current 4-lane portion of Trinity and not a dedicated flow into Central as currently planned: re, the problem of funneling trucks into Central.

I hope the Councilors will give some serious thought to what has been requested before NMDOT finalizes their plans and starts construction.