"Dang, getting a bit stir crazy from driving all day." Brad said out loud, squirming in his seat as a his jeans rip for a horse tail to grow above his rear. "Might need to take a rest stop soon."
His pants rip some more, tears forming over his legs and crotch from his muscles growing bigger as well as the bulge in his underwear. Brad quickly kicks off his shoes and throws them into the back seat, his feet contorting into hooves and having slight difficulty pressing the gas pedal. Of course, it wasn't going to be long before he would have to notice the changes.
"Huh, why do I feel strange all the sudden? OOHhhh NNNeeeeiiggghh!" He softly whinny's and neigh's, his face pushing out more and more till it was now a equines. He glances in the mirror to finally notice what happen, being slightly shocked but felt no fright. "Wow! I'm a horse now!"
Brad looks down to see the outline of his cock under his ripped pants, seeing the 14 inches throbbing and feeling the heavy baseball size balls churning. The arousal was definitely creeping up on him. "Oh yeah, I need to take a break from driving."
Signs soon came into view on the nearest rest stops that were coming up on the closest exit, making a quick decision on choosing the preferred place he wanted to go.