Assume late Victorian era, some crackpot is saying he can make a carriage powered by an engine on it, that can travel over any normal road
Now, steam engines work, so he would probably start with assuming it's a steam engine mounted with tyres of some sort; he'd calculate the rolling friction of a tyre, the mass of the locomotive, and conclude it could barely move along at a couple miles an hour, completely impractical. Which, by the by, is exactly what steam rollers were and about how fast they could go.

So, he gets rebutted, they explain it is a gasoline powered internal combustion engine. He would go into how complicated the timing was for the valving, how dangerous it would be to carry around tens of gallons of gasoline, perhaps throw in a nice picture of a kerosene fire and talk about how difficult they are to put out. Then he'd grant them graciously their wild claim about power to weight ratio, and calculate the speed a 20 horsepower engine could propel a carriage at, and say if you started going 40 miles an hour on normal roads there would be accidents, especially when it was rainy or snowy.

In other words, I imagine he would come up with perfectly valid criticisms of the idea which we hardly think about as we hop in our car and drive 80 down carefully engineered purpose built super highways.