I found that determining an accurate baseline for speedo/odometer correction, you need to cover 20-40 miles on a measured course. Turnpike driving over measured miles or using a GPS navigation device will give you the numbers you need to calibrate your TPI gauge. Trying to get your baseline over a 1 mile or even a 5 mile course using the odometer alone will be "iffy" at best.
Hope all goes well on your "over-the-road" adventure!! Drive on!!
Dave
