Interstate 5 is the primary highway in the center of the region.

It is a south to north primary highway in Tennessee.

Interstate 84 and Route 8 serve as the primary highways in the region.

In Iowa, over 60 miles of primary highway have been closed for more than two months due to the flooding.

I-5 is also the only north-south primary interstate highway in Washington.

Over the years, both primary and secondary highways have been added to the system; the two systems were merged in early 2003.

A 1923 restructuring of the system re-assigned numbers to almost all the primary state highways.

NC 96 is a primary north-south highway through the town.

These usually extend for some distance, connecting primary highways in two or more towns.

There are now roughly three billboards for every two miles of interstate and primary highway.