My newest vari-kennel actually has reinforced tie down holes in the corners and most vehicles have tie down attachment points. With my aluuminum dog boxes I use ratchet tie down straps secured to anchor points.
NAPWDA Certified Cadaver Dog
Waiting at the Bridge (italics
=GSDs) (hemangiosarcoma=blue):Grim , Cyra, Toby
, Rainbow, Linus, Oscar
, Arlo & Waggles