Like the other empires, the Central Union has a road network for each level of government (international, national, territorial, district).
All the Central Union roads follow the same numbering system. Roads going north-south are even-numbered, and east-west roads are odd numbered. The numbers start in the south-west, and grow to the north-east.
Some INNAT roads have 3-4 digits, while others have 2 digits. Also, a few freeways have 1 digit. The number of digits represent the significance of the freeway. One-digit roads are trans-continental. Three-digit and four-digit roads are city routes and have their own numbering system. Two-digit freeways are the standard roads, usually stretching between 2 or 3 countries.
3-4 Digit INNAT Freeways
If the road loops around a to the parent highway, the first digit will be even, and if the road is just a spur from the main freeway, then it's odd. The other two digits are of the parent freeway. For example, if a spur road comes off of INNAT 45, then it will be called INNAT 145.
The international road network is called INNAT (for INTERNATIONAL). The national network is called NAT. Territories have the TET network and district's roads are named. Longer district roads are given the code DIT.