If you are removing an asphalt driveway and replacing it with interlock, do you take out the base material underneath and put 1 foot of gravel or do you just lay the interlock overtop of the old asphalt base?
Yes, usually asphalt will have 4 to 6 inches of base with little compaction. Interlocking pavers require more compaction of the base than asphalt. If not compacted properly your paver driveway will see settling where the cars routinely drive in the same area. Also don't skimp on the pavers if road salt is used in your area. Look at the specs for the pavers and use something with a PSI rating for around 3000 or higher.
Around here you will be lucky to find 3 inches of base. Not uncommon to lay asphalt on dirt in new housing. You gotta remove all of it and start fresh. A geotextile is cheap insurance under the base maerial