xxsq

Not to be cynical, but I get the feeling they will require a Meta account? I'm half kidding but that's what first comes to mind.

The article mentions the smartphone or eventually autonomous cars will be able to time their speed to alleviate the "wait times" at the light. Its not just detection but immediate action thereafter to the vehicle, not just the lights themselves.

There is a a follow up post that is linked in the link you posted which says the following:

As it turns out, Dropbox views/opens certain file types in order to convert them to a compatible format so they are easily accessible via web browser for its users.  This makes sense and is common practice for many cloud storage services to provide the convenience of browser access while not needing any additional software to open these documents.