Press the Menu button
Scroll to Settings and press OK button
Scroll to Personalize and press OK button
Use the down arrow key (located below the "OK" button) to scroll down to Personalize. Press the OK button
Scroll down to "Power Up", and press OK button
Use the right arrow key (located to the the right of the "OK" button) to scroll through until "Accutracking" is highlighted.
When "Accutracking" is highlighted, select "OK".
Press the red hang-up button.
If one of your drivers can figure out how to stop this operation, then he deserves a promotion....

I hope this helps.