Thanks for the ideas! I think I'll try the HD Velcro for starters.
Bill's 3M adhesive looks permanent. I probably wouldn't remove the
carpets except for cleaning but I don't want to have to yank and rip to
get them out. But I may have to go that route eventually. Passengers
usually stand on the carpet to enter/exit and the carpets get pushed
under the pedals. The adhesive may be the only way to really hold them
down.

--JB