There’s too frequently a mismatch between the speed communicated by road design, versus that dictated by a sign. Mechanisms like this overwrite the driver’s intuition, which can only lead to more frustration. Sure, there are incompetent drivers on the road, but that doesn’t mean you have to micromanage the fleet in its entirety. There’s plenty that have a functional brain and are more than competent enough to assess a given situation, irrespective of what a fixed speed limit might indicate. And if drivers used to speed to catch green, that indicates to me the waiting cycles must not have been optimized; and doing so possibly yielding the same result.