Front Plate Required: Yes
Area Codes: 303, 719, 720, 970
License Plates:
Windshield Stickers:
Road and Highway Signs:
County Roads:
Highways:
Highway Adoption:
Historical:
None
Colorado is roughly split north/south by Denver, from the dry grasslands in the east to the Rocky Mountains in the west. Most distance bollards have one or more circles, mounted on a green post. In the mountains, guardrails are marked by three blue or green circles on a green post, and many traffic signs are mounted on a yellow post. Bridges are marked with a sign unique to Colorado, and sometimes run parallel to an older, out of service bridge maintained for historical purposes.
Colorado Coverage
Bollard with green post
Triple circle bollard
Yellow sign post
Colorado bridge marker
Historic bridge next to modern one
East of Denver is mostly dry grasslands, similar to Kansas and Nebraska. However, only Colorado has green post bollards and county roads named with letters. Kansas doesn't use bollards and Colorado's neighbors use numbers for county roads. Missouri also use letters for county roads, but they post a unique sign to mark them.
Eastern grasslands
Lettered county road
White bollard with green post
Small towns consist of one or two-story brick or stone buildings with grid-based concrete streets. The main streets of these towns are usually marked US or State highways.
Eastern Colorado architecture
Main street marked US highway
North and northwest Colorado are scrub deserts, similar to Utah and Wyoming. US highways are marked by white circle bollards with brown-ish posts. Wyoming also uses white circle bollards with brown posts in similar landscapes, but if you see a bollard with two yellow circles, you're in Wyoming, not Colorado.
Scrub Desert
Bollards in the north/northwest
Western Colorado goes from rolling hills to steep gradients depending on what section of the Rockies you're in. Depending on the season, bollards may be double stacked and mile markers are mounted higher. Yellow foliage can help distinguish Colorado mountains from Wyoming, Montana, and Idaho.
The eastern part of the state has concrete interstate highways and circle bollards with green or brown posts. Overpasses all have bridge markers, though sometimes it's attached to a nearby sign rather than the bridge itself. The Denver Metro area has an express lane called "Express Toll".
Concrete interstate highway
Bridge marker on Interstate overpass
ExpressToll in Denver
The only interstate freeway through the Rocky Mtns in Colorado is I-70. Guardrails have green and blue reflectors, and are often brown and rusted.
Brown rusted guardrails
Colorado mountain bollard family reunion
Most of Colorado's urban coverage is in the Denver metro area. Near the city's center, the street name and address are separated by a white line. Outside the downtown area, street signs have a symbol unique to that section of the city. See the City Symbols page for a list of Denver-specific street sign meta. Denver also has about 30 labeled bike routes between Lakewood and Aurora marked by a green oval with a "D" and a number.
Downtown Denver street sign
City symbol map
Bike route map
Idaho also uses green post bollards, though they are flat plastic and the flag is a larger white rectangle.
White marker with green post, Colorado
White marker with green post, Idaho
Texas also uses yellow signposts in certain areas.
Colorado
Thanks to I Necessitate A Visage for pointing out the yellow signposts.