Abstract: A method of determining a calibration factor used to calibrate vehicle speed signals includes the steps of driving the vehicle over a measured distance, counting the pulses generated while driving the vehicle over the measured distance, and then calculating the calibration factor from the number of pulses counted and a nominal pulse count stored in memory. An indication of the difference in a reference speed using the old and new calibration factors is displayed to the vehicle operator who can then choose to accept or abort the new calibration factor.

Abstract: A mailbox signal device for use in combination with rural type mailboxes which are configured with a door having a rearwardly extending flange; or, a door protected by a forwardly protruding hood. The signal device consists of a piece of strong wire or light rod with an eye formed on the rear end and a signal flag of flexible material attached near the front end. The device is loosely attached through the eye of the rod utilizing an existing mounting bolt on and near the rear end of the mailbox. the signal device is free to fall by gravity into a vertical position when triggered by opening the mailbox door. The signal device is made in two configurations. The first has a straight front end. When cocked, it rest on the tab formed on the flange of a backwardly flanged mail door. The second configuration signal device has a hook formed on the front end. When cocked, the hook rest on the bottom edge of a small hole drilled in a lower corner of a hooded type mailbox door.