Back in the day the company I worked for put one of these in my truck. They called me to the office the next day. This was back when the nationwide speed limit was 55. The boss was unrolling the scroll and he stopped at a place and said I was going 70. I said it was downhill. He looked a little further and said the pen was off the chart and got behind the paper and quit recording. He asked just how fast was I going. I told him how was I to know this new speedometer only goes to 70.