When you want your main design element to stand out and be visible from far away, use a loud and bold typeface like Interstate UltraBlack.
That’s why this Interstate is perfect for road signs. Interstate is a digital typeface designed by Tobias Frere-Jones in the period 1993–1999, and licensed by Font Bureau. The typeface is based on Style Type E of the FHWA Series fonts, a signage alphabet drawn for the United States Federal Highway Administration by Dr. Theodore W. Forbes in 1949.
Now that’s a fun little fact!