Weird Runway Markers USA

Recently I flew through DTW for the first time since the reconstruction. I noticed something odd. Next to each of the blue marker lights on the runways is a blue painted STICK mounted in the ground next to the light. Why?

Also at PHX (Sky Harbour) they have the traditional blue lights to guide you, but also some red and green lights embeded in the pavement-NOT to be confused with the runway end go/no go lights.

I’ve always assumed that the blue sticks near the edge lights were to help out the snowplow drivers in the winter.

The green lights are used to mark the centerline of taxiways. Go HERE for a look at one of these lights. They are used at airports that often have low visibility or where the taxiways are very wide and some additional guidance other than the taxiway edge lights is needed.

Red or amber lights are used to indicate hold short lines. These can be on taxiways or on runways for land-and-hold short operations.

Lets see if I can explain this…

Up until 2 months ago, one of our runways was a daytime VFR runway only. At night, it was closed, converted to a taxiway, and used for overnight parking (which made for a helluva oopsie in 1974, but I digress).

This runway didn’t have runway lighting, only taxiway lighting; thus the daytime VFR status. But, it only had lights on one side (blue) and the centerline (green). The edge without the lights had blue reflectors.

The runway (5L-23R) has been converted to a full-time taxiway (Victor), but has retained the same lighting scheme. The area on the “other side” of the reflectors is paved about 60 or 80 more feet away from the official taxiway edge (as it was when it was a runway), perhaps that has something to do with the reflectors.

I’ve also heard in my travels that the reflectors can be used when the edge lights are turned off, but how often does one taxi at night with the lights off at a certificated airport?

As for the red and green lights, its part of a low visibility program called a Surface Movement Guidance Control System, or SMGCS (we pronounce it “smigs”). When the Runway Visual Range (RVR) drops below 1200’, the tower and ground folks institute this plan to keep aircraft and vehicles seperated properly. At our airport, we do SMGCS from 1200’ to 600’ RVR. If the RVR goes below 600’, we close down. We don’t use the embedded Clearance Bar Lights, only flashing Runway Guard Lights (two alternating amber lights next to the hold short line).

If the airport has a SMGCS plan for less than 600’ RVR, then they have the embedded Clearance Bar Lights. Think of them as a traffic light for aircraft. The lights will flash red at the hold short lines and at certain zones on taxiways, and only one aircraft is allowed into that zone. When the aircraft is allowed to move into the next zone, the lights will switch to green. After it passes, the lights go back to red to hold the next aircraft.

FAA has a pretty good description I’ve seen somewhere out there, but the closest thing I could find was this:
http://www.asy.faa.gov/safety_products/guide.htm