There are some rules of the road that are helpful for you to know when planning your touring holiday in the USA, below are a few pointers regarding driving licence requirements, insurance, speed limits and some of the travelling costs that you can expect to incur.
Vehicles drive on the right-hand side of the road in the USA. The use of seat belts is governed by state, not federal, law. All states have seat belt laws for children, almost all have them for adults and the use of seat belts by all vehicle occupants is strongly recommended. The USA has an excellent highway system and rules of the road are broadly similar to Europe. 
If at traffic lights there is a “Right on red” sign, you are allowed to turn right through a red light provided that the way is clear.
When a yellow school bus stops and its red lights are flashing, traffic travelling in both directions must stop.
Highway speed limits are typically 55-75 mph but can vary from state to state, so pay attention to the black on white speed limit signs (you may also see white on black signs, headed 'NIGHT', if a different limit is imposed for night time driving).
Tolls may be payable for tunnels and bridges, or for some stretches of road also known as turnpikes. Turnpike tickets issued usually include the time of entry, so that a fine can be issued should your time on leaving the turnpike indicate a speeding offence.
The America the Beautiful pass is worth purchasing if you intend to visit several of the National Park. A list of the National Parks included in this scheme are listed here. The pass can be purchased when you enter the first of your National Parks.
Officially, a full UK driving licence is accepted on its own for a period of up to one year, without being backed up by an International Driving Permit (IDP) which verifies that you hold a valid driving licence in your own country.
In practice, many hire companies, as well as many police officers in the event of an accident or a routine check will not be content unless you can produce an IDP, so we strongly recommend that all drivers obtain one.
This must be done before travelling. An IDP costs £5.50 and is easily available from the Post Office – click here to find out more. 
On individual, tailor-made holidays, depending on your rental company, your motorhome rental includes Vehicle Incident Protection (VIP). This reduces your liability to $1,000 per incident. At all times you are responsible for up to $1,000 per occurrence as a deductible excess. It also includes coverage for public liability, property damage and/or personal injuries, limited to the minimum financial limits determined by the US state (or Canada province) in which the incident occurred.
Supplemental Liability Insurance (SLI) can be prepaid at the time of booking and covers the difference between the underlying insurance and up to $1,000,000 against claims by a third party for bodily injury and/or property damage resulting from an accident. There is no deductible excess with the SLI. An imprint of a major credit card is required while the motorhome is rented.
Fuel is known as gasoline or gas. For motorhomes it is always unleaded and generally costs far less than fuel in the UK, being generally cheapest on the Gulf of Mexico coast and more expensive as you go further north, east and west. The price can also vary depending on whether you use a ‘full-service’ or ‘self-service’ garage. Credit cards are widely accepted. You have to pay before you fill up, which means deciding in advance how much fuel you want to buy. It is usually easiest to start off in increments of $100, until you get to know your vehicle’s fuel usage.
Click here for current fuel prices by region. 
It is a criminal offence to operate, or to be in the care or control of, a vehicle, whether in motion or not, with a blood alcohol content (BAC) of more than 0.8mg. Some studies suggest that at this level you can be up to 11 times more likely to have an accident than with a BAC of zero, which is the recommended level for driving. Driving under the influence of alcohol or non-prescription drugs is taken very seriously in the US.
The legal age for drinking or for public possession of alcohol is 21; some states specifically prohibit minors from drinking alcohol while others permit it. In many states it is illegal to carry an open alcohol container in a moving vehicle or in a public place. In some states opened alcohol may be permitted in a parked vehicle if kept away from the driving area and the driver, but check this with your campground on arrival.