Those who travel on freeways are dependent upon exit signs being clearly marked, and though many a person prefers the actual name of the exit that they are taking, it has to be said, that probably a lot more, actually prefer the exit number as of being more important, for names of exits can be fairly similar or sound about the same, whereas exit numbers are absolutely distinct. Because this is the United States, there aren’t always the exact same formal standards that each State follows when it comes to their exit numbering, of which, logically the best numbering system is to begin at the number 1 for those entering the State as in, for example, from the western direction, and then to tie in the exit numbers to the distance so being traveled eastward, which aligns with the mile markers, that are often posted on one side of the road. That is to say, exit 3 should represent having traveled 3 miles in an eastern direction, and if the next exit isn’t until another 8 miles, that should be labeled as exit 11.
When it comes to the accuracy of mile markers and even mile markers that are further broken down into tenths, such as .1 mile, .2 mile, and so on, this signage if it has been deliberately created to provide that specific information is going to be very accurate, because it has been engineered to reflect an accurate distance; so then, it can be taken as a given, that any signage, which is specifically meant to show mileage, is accurate. On the other hand, there is plenty of signage that has been posted onto a freeway overpass, of which, that signage is going to be susceptible to being not so accurate, because overpasses are designed first and foremost, as a way and means to travel from one side of a road to another, and has little to do with being placed, for instance, exactly one mile from a given exit. This means, that those who note mileage signage on an overpass, that tells the driver that they are 1 mile away from an exit, can be inaccurate, by as much as ¼ mile, in either direction, thereby, indicating that those traveling at a high speed, may not have as much time as they think to get over to the exit lane, and why some people believe that a given exit, just seems to come up too quickly, or for those signs, which are underestimating the distance, why it seems to the driver as if that mile is a very long mile.
The thing about GPS and driving is that GPS is very accurate, and those then that rely upon GPS for their navigation are relying upon an instrument that almost always gets the distance and the exit, correctly. When it comes to freeway signage, though, it isn’t so much that engineers can and do make mistakes, though they do, but rather it has a lot more to do, with the signage, especially on overpasses, as being an aid to the driver, but not meant oftentimes to be taken literally, for as they say, your mileage may differ.