We've done signs, interchanges, signals, how about photos of old street lights?
Here's some that I have for now:
A picture of a old (presumably mercury vapour) clamshell or rounded style streetlight near the intersection of ON 48 and Stouffville Road.
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fimg40.imageshack.us%2Fimg40%2F3356%2Ffscn5393.jpg&hash=e36f450e52103acd2280b64d3a08da22426fd387)
A string of some old style fluorescent tube style streetlights near Newmarket Ontario:
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fimg40.imageshack.us%2Fimg40%2F6857%2Ffscn3846.jpg&hash=711f1964996e458dfa1901b316e6b88cf47250c8)
And finally a closeup on one of the fluorescent lighting fixtures:
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fimg40.imageshack.us%2Fimg40%2F508%2Fdscn3789.jpg&hash=c670c06dd134c286cad5570d4a825f9bc1ae875e)
I have shots of a number of old street lights in and around Cincinnati here: http://homepage.mac.com/jjakucyk/Transit1/lights/index.html
I've seen low pressure sodium at the top end of I-495 around Boston.
There's also low pressure sodium in Safford, AZ on really neat poles here (http://maps.google.co.uk/maps?f=q&source=s_q&hl=en&geocode=&q=safford+az&sll=53.800651,-4.064941&sspn=20.193763,56.90918&ie=UTF8&hq=&hnear=Safford,+Graham,+Arizona,+United+States&ll=32.834957,-109.727883&spn=0.013594,0.035963&z=16&layer=c&cbll=32.834954,-109.728077&panoid=xg_9_cHeWQYm5NEBqyWQiA&cbp=12,277.42,,0,-8.59).