Can my dog ride in the back of my pickup truck?

In WY farm and ranch dogs ride in PU beds. Probably dangerous where ever they ride. Just get in the PU and start the engine and the dog jumps in. Ever come out of a Walmart and find a strange dog in your PU bed? It seems to be instinct on their part. If they get lost they will get in the nearest PU bed that looks like their PU. Plus don't ever get too close to those PUs. The PU belongs to the dog.:B