what is the speed limit in tennessee?
 The only auxiliary interstate in Tennessee with a 70 mph speed limit is Interstate 840. 70 mph speed limits are allowed on all other controlled access highways, and are found on controlled-access portions of U.S. 27 and 51 and S.R. 22, 111, 386, and 396. In 70 mph zones, the default minimum speed limit is 55. 