I recently moved to Western Massachusetts from New Hampshire, where speed limit changes of 10+ MPH are always marked with "reduced speed ahead" signs. According to the Massachusetts government website: "Reduced speed limit ahead signs are used to inform road users of an impending reduced speed zone where the speed limit is typically being reduced by 10 mph or more". There are several places along roads I drive somewhat frequently, such as the U.S. 202 highway, where the speed is reduced by 10 MPH or more with no warning signs, often right after corners so that it's impossible to see the signs with enough distance to safely slow down before passing them. For example, there any many places where the speed drops from 50 to either 40 or 35 with no warning, and even a place where it drops from either 45 or 50 (can't remember) to 25 with no warning, and from 35 to 15 in another spot, a reduction of 20-25 MPH. None of these places are marked with "reduced speed ahead" signs, and many of them are right at the end of corners that are impossible to see around because of trees, etc. This leads me to believe that there must be some law in MA that allows drivers a certain distance to slow down after passing a speed limit sign of a lower speed without it being considered speeding, but I cannot find any information about this from my online searches. If there is no law allowing this, then are these towns breaking the law by not putting up these "reduced speed ahead" signs when dropping the speed from say 50 to 25, or 35 to 15, with limited visibility along a U.S. highway?