See the Tests and Research section of the following NTSB report on a Delta incident where a plane landed on a taxiway at KATL. Note Also that the lights had been recently updated with LEDs from incandescents. Basically, the taxiway centerline was brighter than the runway centerlines and the colors of the lights were only apparent at 500ft.

https://www.ntsb.gov/about/employment/_layouts/ntsb.aviation...