I-15 in San Diego County is full of these light poles. Most have either LPS or HPS full cutoffs. However look at the second pole in this pic, it still has its original GE M-1000 700w merc light from '77.
Tmcdllr: Are you referring to the ones on CA 237 in Milpitas? There is a stretch of them through the city.
Update everybody: I found that this interchange photographed above was completed and opened to the public in May 1978. All the leaning davit poles installed during '77-'79 originally had mercs.
i notice you put 310W HPS for the M400A3....i've heard they only use 310 Watts in Chicago and CA,how difficult would it be for a collector to come across such a lamp?
UPDATE: sadly the M-1000 is no more. it fell victim to a knockdown. a new leaning davit pole with an ael 325 lies in its place. theres still one M1000 left at this interchange down this ramp.
BTW, Devonte, the reason for 310W HPS lamps is that they're designed soley to replace 700W MV lamps on a lumens basis (they have comparable lumen ratings)
Update everybody: I found that this interchange photographed above was completed and opened to the public in May 1978. All the leaning davit poles installed during '77-'79 originally had mercs.