§1. In the United States, automated license plate readers are becoming more and more common, particularly on toll roads.

A unform national format and numbering system for license plates will ease operation of these plate readers. In particular, it will resolve uncertainty about which jurisdiction issued a plate, because at present two jurisdictions might issue separate plates that happen to have the same number for two completely unrelated vehicles.

It is not necessary that all license plates be changed at once. Some jurisdictions will begin issuing these before others; and license plates are often used a decade before being replaced. As a result, a long phase-in period is to be expected.

§2. In this proposal, each plate has one or two lines containing the license number, which is a sequence of letters and digits. Many jurisdictions will choose to put their name and motto at the top or bottom; the examples given here include that.

Each plate uses a two-letter abbreviation as specified by the United States Postal Service (USPS) for that jurisdiction. These abbreviations were chosen because they are widely known and used. There are fifty states, the District of Columbia, and several territories. One addition for this plan is to use "US" on plates issued by the United States government for Federal vehicles.

Jurisditions with a large number of vehicles might benefit from being assigned multiple two-letter abbreviations; for instance, California might be given both "CA" and CB"; New York "NY" and "NZ".

The first line, or the only line, of the plate begins with that two-letter abbreviation. Remaining characters of the first line, and all characters of the second line, are chosen by the issuing jurisdiction freely.

License plates for automobiles and most other vehicles are 12 inches wide by 6 inches high. Those for motorcycles, and in some jurisdictions trailers, are usually 7 inches wide by 4 inches high. These smaller plates are limited for practical reasons to a one-line number; and the motto will probably have to be omitted.

§3. Here are sample images, which include the month-and-year expiration stickers that many jurisdictions use. Ideally, all jurisdictions would agree on the font face, font size, character spacing, and related graphical details.

The exact appearance of text in these images will depend to some extent on the user's browser.

plate 1 plain one-line	plate 2 plain two-line
plate 3 two-line with logo	plate 4 for motorcycles and some trailers
plate 5 one-line commemorative	plate 6 two-line commemorative

Plates 5 and 6 are examples of the commemorative plates issued by many jurisdictions for schools, charities, native American tribes, military veterans, sports teams, et cetera.

§4. Many states on their license plates include an indication of the county in which they were issued. One way to do that on the plates proposed here is to use one, two, or three characters after the two letters of the state abbrevation:

• Delaware, with 3 counties, could easily use one character.
• Texas has 254 counties, each with an official two-letter abbreviation and an official three-digit number, either of which might be used.
• Ohio has 88 counties, each of which has a three-letter abbreviation assigned by the Ohio Department of Transportation. Alternatively, a two-digit number would work.

Texas counties				Ohio counties
Anderson	AN	001		Adams	ADA	01
Andrews	AD	002		Allen	ALL	02
Angelina	AG	003		Ashland	ASD	03
… continuing …				… continuing …
Young	YN	252		Williams	WIL	86
Zapata	ZP	253		Wood	WOO	87
Zavala	ZV	254		Wyandot	WYA	88

In place of county codes, special codes could be assigned for plates to be used on the states's own vehicles, and for plates used on the vehicles of intercounty government agencies and municipalities. A prominent example of the latter is New York City, which covers five full counties of New York State.

§5. Many jurisdictions provide various kinds of license plates for different kinds of vehicles. Typically, registration and plates for large, heavy vehicles cost more than for small, light ones. The exact categorization varies from place to place, and farm vehicles are often given special consideration.

An option for the license plate number is to include, perhaps at the end of the first (or only) line, a character to indicate the the vehicle's classification. A possible scheme:

• one letter for each kind of heavy truck, tractor, semi trailer, and full trailer;
• one letter for buses;
• one letter for each kind of farm vehicle;
• one letter for motorcycles;
• a range of digits for ordinary automobiles and small pickup trucks, because they are in large quantity, forming the bulk of the vehicles on the road; along with one letter for the light trailers that they pull.

If jurisdictions were to establish a national standard, it would make calculation of fees for toll roads simpler, because nearly all toll roads charge more for large vehicles than small.