The contrast on those looks really bad compared to the normal ultra high contrast color schemes used in road signs. I'm not sure that reliability is more important than visibility.
The fact that they don't break down is just a further testament to e-paper's versatility - we'll see more and more applications using e-paper in digital signage. There's a lot of examples what our customers are building on our blog, like smart citizen information (https://www.visionect.com/blog/soofa-sign-reinventing-citysc...) or trucks equipped with digital signs (https://www.visionect.com/blog/electronic-paper-truck-displa...).
How many employees could be hired changing the physical road signs given the price difference?
Given the positive feedback from the end customer and Mercury Innovation (http://www.mercuryinnovation.com.au/) that took our platform and built the traffic sign (we're not the ones selling the end product) I'd say that TCO is in favor of e-paper traffic signs.
Disclaimer: I work for Visionect
Judging by their posts on this page, the company that manufactures the signs is clearly hooked up to an IV drip of their own koolaid. Still, for this particular application (temporary parking restrictions) e-paper is much better than the previous solution, which was to print plastic inserts and drive around the city sliding them into tracks on the signs.
Also normal road signs use retro reflective spheres mixed into the paint to increase brightness at night, not sure if those can be carried over to e-ink displays?