The rest of the system flows from this most basic starting point. The canon of literature on this starts with ZZYZXs Interstate Page.
For example interstate 5 I-5 goes all the way from the Southern border.
What do freeway numbers mean. I-405 loops with I-5 and I-384 veers off from I-84. Two digit or single digit numbers. Here National Routes are replaced by Strategic Tourism Routes.
A 3di takes the number of its parent and adds a multiple of 100. An even digit for a road that loops. Tire companies use this to recall defective tires.
Primary interstate highways in the United States have one- or two-digit numbers such as I-5 and I-84. Motorway primary route regional road etc general geographical location in zonal numbering systems andor. Three-digit interstate highways or 3dis branch off or loop with the primary routes.
Generally northsouth highways have odd numbers that get higher from east to west while eastwest ones have even numbers that get higher from north to south. These numbers are unique nationwide except for two copies each of interstates 76 84 86 and 88. Auth Used to change a designated highway from one number to another within the same State Highway System ie from SH 75 to SH 91 or to redesignate a Farm to Market Road as a Ranch to Market Road.
Map of the Interstate Highway System. For more information and a sample map. Heres some of the language of the freeway.
All two-digit routes are signed. All major freeways that span across several states have one or two-digit numbers. A glossary of terms having to do with Highway Designations.
The words highway and freeway are used interchangeably but there is a difference between the two and understanding what that is allows you to use both words correctly. First how many digits The number of digits tells you whether an interstate connects multiple metro areas or exists solely within a single metro area. The last two numbers indicate the parent route and the first digit signifies the roads function ie an odd digit for a spur running directly to a city.
Odd number means the freeway runs north-south while even numbered freeways travel east and west. Ultimately the two words are used to mean the same thing and most people arent even aware there is a difference between highway and freeway. Counting left to right The California Department of Transportation numbers each freeway lane from left to right the left lane labeled No.
Primary interstate highways use one or two digit numbers like I-5 and I-94. Only route number 1 is kept as National Highway 1 and the other roads do not match the national system anymore though there is no duplication. Major routes mostly end in 1s and 0s while three-digit numbers tend to represent secondary or spur highways.
The next 3-4 tire numbers are an optional code for the manufacturer. A route or road number designation or abbreviation is an identifying numeric or alphanumeric designation assigned by a highway authority to a particular stretch of roadway to distinguish it from other routes and in many cases also to indicate its classification eg. One and two-digit interstates span multiple regions while three-digit interstates are more local.
By the way you can check whether your tire company has recalled your tire model here. Numbers are unique only per state for example there is a C325 in Victoria but also in Tasmania. Odd numbers run north and south.
The code should include the category of the tire its construction and tread pattern. Even numbers run east and west. Queensland is a special case.
Routes ending in 0 1 or 5 are usually highest priority routes though all Interstates are very important to state maintenance.