Posted by Trumpy:
Peter,
Why is it that a lot of local authorities are stipulating Metal-Halide over HPS or any other such slack lighting source.
I don't know, but I know that's not the case in the United States. The vast majority of public roadway lighting is HPS here, with a lot of Mercury Vapor still in use.
The standard probe start metal halide lamp has a life of 10,000 to 15,000 hours. HPS is well over 24,000 with better lumen maintenance.
Futhermore, with the extremely high cost of maintaining thousands of street lights, the long life, high lumens-per-watt and passive failure mode of HPS give it clear advantages over MH.
Peter
