"Welsh designer Ross Lovegrove (’Captain Organic’) placed several glowing Solar Trees in the streets of Vienna (October 2007). These solar powered streetlights could save cities energy. Unlike regular streetlights, they do not require costly underground wiring to install, they are immune to blackouts."
"The lights have 10 solar panels arrayed at the top of tree-like branches, which charge built-in batteries."
"The trees also incorporate light detectors, so the lights automatically turn on sunset and off at sunrise."
This makes sense to me so I can expect that it will not be introduced into the cities in the United States.