Thursday, May 21, 2015

Self-contradictory highway sign

We occasionally pass this sign on the way to work:
I'd like to point out a few things:
  1. This picture was taken from the passenger side of the car. Be safe when driving!
  2. The splotches are an artifact of a refresh rate, moving car, and cellphone camera. In real life, it looks solid.
  3. I am incredibly annoyed by the different fonts and sizes of the two different 13s. It's a digital sign with digital fonts, not sure how this screwup happened.
  4. Finally, the left part of the sign says "13 MILES  l3 MIN" And yet, the speed limit sign says 55mph. Which is it, folks? At 55mph, it should take 14.1 mins to travel 13 miles, so rounding to nearest integer, it should say "13 miles 14 minutes". On the other hand, if you're travelling at 55mph for 13 mins, you travel a distance of 11.9 miles, so rounding to nearest integer it should say "12 miles 13 minutes". In fact, using rounding (nearest integer, ceiling or floor) there is no way to get (rounded to 13) miles in (rounded to 13) minutes. So, I think it's safe to drive at 60mph there, and rely on physics in when you get a ticket.


  1. This is the NJ turnpike, right?
    Figure 9.75 minutes.

  2. Also, if you drive at 55 mph on the NJ Turnpike make sure you have your blinkers on so you don’t get rear-ended because you are moving so slowly

  3. However, when I drive to work, it's more like 13 miles, 31 minutes.