Let me get this straight: it has no armour, no weapons, and no military equipment?
Well, that pretty much rules out tanks by my definition…
I don’t imagine there are rules per se on the appearance of the vehicle, but there will be (as said) on noise, weight, hull thickness, possibly emissions and safety, and general roadworthiness (e.g. lights).
Naahhh, tanks are lame 'cause you have to give up the main aspects that make them great to be able to get them! Now submarines on the other hand!
You should join my wacky-wehicle-idea-bandwagon™ and get yerself your own sub!
If you think that’s crazy, I even found a damn site that sells the things! http://ussubs.com/
As soon as I raise the small fortune they cost I’m gonna go live under the sea, away from the problems of dry land!
launches into “Under the Sea” song from the Simpsons
— G. Raven
I don’t know about the U.S., but one time in Bannockburn, Scotland, I saw a tank tooling down the public road. Actually, we saw several during the years that my parents lived there, but this one stuck in our memories, because it had a “STUDENT DRIVER” placard!
We gave it lots of room.
Yeah, I know. Tracked vehicles, like bulldozers and tanks, fall under the “exempted” category when operated by either military personnel or authorized personnel of the Department of Transportation, OR commercially licensed heavy equipment operators. Since, I assume you do not belong to any of those classes, you cannot drive a tank.
The issue of a homemade vehicle is something entirely different. Let’s say you built a lightweight tank that fully met all of the federally and locally mandated safety requirements. Your local DMV has full discretion in whether or not to allow it on the road. (It is an experimental vehcile, after all.) Additionally, they’re unlikely to allow you to drive unless you belong to an exempted class, or ar licensed to operate heavy equipment.
So, evilhanz, what you’re saying is to get a real tank with weapons and crap, and MAKE them let me drive it? 
Kidding of course. We need an authority on this one, it seems no one can give me a proper answer. Even if we had an authority on experimental vehicles that would be fine as well… anyone anyone?
Will you paint it yellow, too?
For what it’s worth, I used to drive an APC in the ARMY. All I had to have was a licence and pass a dorky eye foot reaction test. For my trouble I was given a licence that stated I could drive any vehicle under a weight of 70 tons. (No drivers class or anything) We had one guy run over our diesel fuel pumps in the motor pool. They did NOT take away his licence. My favorite sport was to look for potholes in the road and hit them going 45mph downhill in a M577. Scared the shit out of every one in the vehicle. (These things do not handle well at this speed.) I had my Tank Commander fly out of the the TC hatch into the generator cage.
I was going to buy a tank once…
I lived in the Mojave Desert and I thought it would be neat to go around in. AFAIK, there is no “license” to drive a tank. The catch is that tanks are (generally) prohibited from on-road operation. These things are heavy and treads really tear up the asphalt.
If you want to drive your tank around off the highway, I’d assume it would be the same as using your dirt bike or sand rail. Trailer it to the OHV park or private property or government property where it is permitted to operate off-road vehicles and have fun. Load it up again for the trip home.
FWIW, the on-road problem with tracked vehicles is generally not their tracks per se but those darn metal lugs. In some agricultural applications track-type tractors are preferred because they don’t compress the soil nearly as much. The tracks distribute the weight over a much larger area than tires do. (That’s why some really big farm tractors have dual wheels – to distribute the weight better.) This is also one key to their superior traction – they sink less into soft soil. But the metal cleats on the tracks do significant damage to paved roads and are not allowed. If you use a Caterpillar bulldozer* for a farm tractor you have to load it on a trailer to move it from field to field, which is impractical.
Which is also the reason Caterpillar came out with a rubber-belted agricultural tractor several years ago – you could drive it down the road without getting the county DOT up in arms. AFAIK, it’s been a successful product. I’m sure it’s most often roaded under an “exceptional use” clause but you could probably get a license (for the tractor) if it also complied with taillight and rear-view mirror, etc., requirements.
OTOH, most construction (and military) equipment is very heavy, so it’s not just a matter of spreading the weight out. The deflection caused by the vehicle in the roadbed, which is the chief culprit in wearing a road out) goes up as the fourth power of the weight! So if you build your armorless, weaponless tank make sure it also isn’t too heavy or you’ll be asked to pay a hefty road tax, like semis do.
As far as steering, most tracked vehicles use a “clutch and brake” assembly on each track which can selectively drive or brake either side independently, but both tracks move either forward or backward together. Fully independent drive trains are not uncommon, however, with each track independently powered and able to go in forward or reverse. This is important for maneuvering so most construction vehicles that need to work in tight quarters (excavators, track-type loaders) have this kind of steering. They can turn around in place. This is usually done with a hydraulic transmission but it can be done mechanically as well.
*Technically, the term “bulldozer” refers to the blade (and it’s a particular type of blade) not the vehicle. The official Caterpillar designation for the vehicle (while I was there) was “Track-Type Tractor”.