eh, yard cart was an exageration. those buggy things they sell at gander Mtn are "legalizable". as long as you have a bill of sale and they have the required parts like proper lighting and signals, DOT tires a horn and wipers, you can get them street legal.
thats why i was wondering what keeps the hijets off the road?
The CFO of the company, or whoever is in charge of the wallet, that's who.
You're right, you or I could buy one, and go through all teh steps and make it road-legal as mentioned above. But guess what, that's not free; addin gall that stuff takes time+ resources = money. Take a vehcile that's already fairly pricy, compared to a bike, small truck, or whatever, and add that extra cost... hard to justify total expense (from a business end).
Now that is for the folks who'd be BUYING them.
Why aren't they just sold as being road-legal?
Well, b/c that requires the seller to do all the extensive NHTSA testing, protocols, etc... making it "safe"... big $$ on their end. That is, if it will be SOLD as a DOT-approved vehicle. Plus, it's a whole level of liability for them. So, instead they save $$ by not doing that stuff.
And think of this - if you bought one, and made it "rroad worthy" by doing the above, but did nothing to improve the safety... sold it to me, then I drove it on the road and got flatted by an SUV... I could probably sue you. Not that it's the "right" to do so, but legally possible....