Minimum view distance for road signals - an important information from Knoxville News Sentinel

http://www.knoxnews.com/story/news/2017/07/03/safety-concern-papermill-intersection-prompts-action/414437001/

It is stated in the above article, regulations require 390 feet clear view distance for vehicles moving at 40 mph. That is for vehicles moving at 40 mph speed (59 ft per second), sight distance time to see signals is recommended as 6.65 seconds.