Plenty of opinion has already been said, but hash out the law referenced by +Matt Abdou
The law defines five classes of permitted electronic screens in cars. They range from GPS, to info displays, all the way to video screens that are design to not be used when the car is moving.
What would be key here is how the court would see the device, two scenarios come to mind:
A) Ticket is void:
Glass' main use in a car would be for driving directions -- therefore it is a mapping device; or
B) Ticket is valid:
While Google Glass can be used as a mapping/navigation device, police have no way to know the user isn't watching video and therefore it is a class 5 device that fails the required safety mechanisms.
The rest of law is exemptions for utility workers, cops, and emergency workers.
Really, it would depend on the judge you get.
Disclaimer: I'm not a lawyer, don't take it as legal advice. Just food for thought.