Sydney is now using the world's first outdoor e-ink traffic signs to guide motorists during special events. The city's Roads and Maritime Services (RMS) agency was apparently fed up with the constant chore of changing signs, and developed the tech with a company called Visionect. Like your Kindle, the signs are easy to read in Sydney's bright sunshine, which also powers it via solar panels. There's a light for nighttime usage, and the messages can be updated remotely via a cell connection to an "internet of things" network.