The Colorado Highways Site: About
About | Colored
Table Format | Info Given About the Routes |
Abbreviations & Terms | Sources
About This Site
This site's purpose is to explore the past, present and future of
Colorado's state highway system. The general idea is to log
information for all of the numbered highways in the state,
information such as where they end, where they go, how they get
there, their history, etcetera. This site started out in rudimentary
form in spring 1997, after having seen similar sites for several
other states. When I decided to undertake this effort, I never
imagined I would have spent as much time on it as I have, but I have
stuck with it. The site is a constantly evolving, growing thing. I've
basically just been continually building to it since 1997. The main bulk of the site is made up of pages that list
numerically each numbered highway -- state, US and Interstate -- that
has ever existed in Colorado.
Comments? Questions? Concerns? My e-mail address is at the bottom
of every page.
As Always, There Are Disclaimers:
THIS IS AN UNOFFICIAL
SITE. It is not affiliated with or endorsed by the
Colorado Department of
Transportation, the E-470 Public
Highway Authority, or any other official agency. The opinions
expressed here are mine or a fellow citizen's, not of the government
of Colorado. This site is meant for general information purposes
only. 100% information accuracy cannot be and is not guaranteed.
COPYRIGHT INFORMATION: This site ©
Matthew E. Salek, 1997-present. All text and images are created by myself
unless otherwise noted. Use of text and images where I am originator is
authorized as follows: Use prohibited for any commercial/profit
purpose. Use for non-commercial purposes is allowed under "fair use"
(meaning credit is given). A special note on photographs: Many of the
photographs shown on this site are not mine, they are given to me. Any
use of a photograph taken by someone else is prohibited unless
authorized by that person. Thank you for not stealing!
Colored Table Format
When browsing my route listings, you will
notice that different routes are in different colors. This is done to
quickly convey whether a route still exists or not, and if it
doesn't, when it became defunct. Theses colors do not apply to the
Auxiliary Routes section of my site, nor the US/Interstate Highways
White: Currently Active
These are signed routes that currently exist in the
Colorado highway system. Some of them may not be marked
in the field very well, but they do exist.
Gray: Pre Mid-1950s
This color is used for routes that became defunct
before the mid-1950s.
Yellow: 1940s Route
This is a special case. This color indicates a route
that, as near as I can tell, existed only around the
1940s. These are routes which were brought into the
system in 1939, and disappear in 1953. There are a lot of
them. A write-up on these routes can be found on my
Green: Mid-1950s to 1968
This color is used for routes that became defunct from
the mid-1950s to 1968.
Routes which have this color in the table are routes
that became defunct after 1968.
Orange: Unknown, Never Signed,
Carrier Route, Other
This color is used to indicate several cases:
- A US Highway that was proposed, but never ended up
- A state route which I have never found evidence of
existing. Colorado appears to not have skipped numbers
up through at least 403, but below that there are
several routes I have never found on a map.
- A route that served mainly or only as a carrier
route. That is my term for a state highway that
appears to have been used mainly or only as the state
number along a roadway that was a US or Interstate
- A route whose current status is unknown.
- Other. Read the explanation.
Information Given in the Route Tables
This section explains the info that is given about each route
in the route tables.
- Location: This is the highway's location in the state.
I have divided up Colorado, somewhat arbitrarily, into sectors
called Western Slope, Mountains, San Luis Valley, Northern Front
Range, Metro Denver, Southern Front Range, Eastern Plains, and
Arkansas Valley. Here's a map. When a
highway crosses from one sector to another, I'll say "Metro Denver
> Eastern Plains". If a highway is really short so that it is
only in one city, I will give the city as the location.
- Length: Given in miles. Lengths with an * are official
mileages down to the 0.01 of a mile out of the official CDH/CDOT
sources. Lengths without an * are estimations on my part using a
variety of sources.
- Termini: The two endpoints of the route in Colorado,
given in the direction the route is defined in CDOT sources.
- Nationally: If the route goes outside of Colorado, the
national endpoints will be given along with the total national
- Counties: Counties the highway passes through or
- Places: All incorporated cities the highway passes
through, as well as notable unincorporated places, canyons,
- NHS: If part of the route belongs to the National
Highway System, this will indicate which sections. The NHS is a
system of major highways that get partial federal funding.
of the system are available from the FHWA.
- Freeway: This will appear and explain any sections of a
route that are access-controlled with interchanges.
- Expressway: This will appear and explain any sections
of a route that are 4-lane high-speed expressway.
- Spur Connections: Any spur connections, officially
defined in CDOT sources, are noted. If a link is present, it will
take you to additional info about the spur on the Auxiliary
Routes section of my site.
- Business Routes: Cities in which the route in question
has a business route. Links will let you view the information on
the BRs on the Auxiliary Routes section
of my site.
- Broken Route: If a route is "broken", meaning
discontinuous or having gaps in it, this will appear along with a
- Mountain Passes: If a route goes over any mountain
passes I will give the pass name, elevation, and other notes.
- Sections Closed in Winter: If a certain section of a
route is closed every winter, this will note the location of the
- Roadway Names: If a route is known by any other common
names this will appear along with the name.
- Memorial Designations: Designations conferred on the route by the state legislature.
- Scenic and Historic Byways: If sections of the route are part of any of Colorado's official scenic & historic byways, and if any of those have America's Byways status. An "All-American Road" is an even higher status of an America's Byway.
- Notes: Little tidbits of info for the route.
- Milepost Guide: This section lists, to the 0.01 of a
mile, where the route in question intersects other state highways.
If a route's only intersections are its end points, this is
- Annual Average Daily Traffic: Lists traffic counts
(from CDOT sources) at various points along the route. The data is
much more exhaustive than I list.
- Guide: A narrative description of the where the route goes and what it encounters along the way.
- Photo Gallery: Links to photos I or others have taken
of the highways. The photos are also shown in the Photo
- History: Historical info I've been able to dredge up
will appear after this.
- Suggestions: Here I offer suggestions for what I feel
would be improvements to the route. Listening, CDOT?
- Related Sites: Other sites with info relating to the
Abbreviations and Terms Used
All of the various compass directions are abbreviated with one or
two letters. States and provinces are abbreviated with the two-letter
postal code. Other abbreviations and terms:
- AADT: Annual average daily traffic, a way to express
the average daily number of vehicles on a stretch of roadway,
determined either through actual measurement or statistical
- AASHTO: American Association of State Highway and
Transportation Officials. They set the rules for US and Interstate
route numbering, and set design guidelines for roadways.
- Aux Lane (Auxiliary Lane):
A lane on a freeway which is a continuous lane on from an entrance ramp
but becomes an exit-only lane at the next interchange. Aux lanes are
not included in the total number of through lanes a freeway has, since
they are disjointed at each interchange. For example, I-25 south of
I-225 has six total lanes each direction between interchanges, but
because one of those is an aux lane, I-25 is considered to have only
five through lanes each direction.
- BL: Business loop
Burlington Northern Santa Fe Railroad, one of Colorado's two major rail
companies. Maps that have any rail lines labeled as Burlington Northern
or Atchison Topeka Santa Fe are actually BNSF rail lines.
- BR: Business route
- BS: Business spur
- BYP: Bypass
- Carrier Route: Term I use to describe an SH route that
served primarily or only as the SH number along a stretch of
roadway that was a US or Interstate highway. Before 1968 the state
gave every stretch of highway in the state an SH number, even if
it was only marked in the field as a US or Interstate.
- CDH: Colorado Department of Highways (up to 1991)
- CDOT: Colorado Department of Transportation (since
- C-D Road: Collector-distributor road, a kind of road at
an interchange which branches off of the main line and then feeds
traffic onto multiple ramps. Example: All four directions at the
- CO x: Colorado Highway x. The routes signed with the
state route marker.
- CR: County road
- DBT: Denver-Boulder Turnpike
- Decommission: Term used usually to mean when a US route
is taken out of service. Can also be applied to other kinds of
- Defunct: A numbered route no longer in existence
- Expressway: A multi-lane divided highway that still has
intersections, but may have the occasional interchange
- Expy: Expressway
- Freeway: A multi-lane divided highway with access only
- Fwy: Freeway
- HOT Lane:
High occupancy or toll lane, special lanes set aside for vehicles that
have two or more people in them, or for single occupant vehicles that
are willing to pay a toll. In Colorado the single occupant vehicle
tolling is done with ExpressToll electronic toll collection. The toll
may be variable by time of day. See the next entry for additional rules
for high occupancy vehicles that want to use HOT lanes. HOT lanes have
been given the derisive nickname "Lexus Lanes" by critcis, on the
belief that rich, single occupant drivers can use the lanes to bypass
the commoners in the congested general purpose lanes.
- HOV Lane:
High occupancy vehicle lane, special lanes set aside for vehicles that
have two or more people in them. In Colorado motorcycles and
alternative fuel vehicles are allowed to use HOV lanes even with only
one person. ("Alternative fuel vehicles" means things such as ethonal
or propane powered. Gas-electric hybrid and flex fuel vehicles don't
- Loop Ramp: A form of ramp at an interchange that
usually takes the driver 270 degrees around to the right, like
would be found in a cloverleaf interchange.
Milepost. Mileposts generally increase heading east and north along a
highway. CDOT tends to use MM (mile marker) in public information
Manual on Uniform Traffic Control Devices, the book put out by the
federal DOT which sets sign, signal and pavement marking practices for
the US. CDOT issues a state supplement to the MUTCD to include
Colorado-specific signs for things such as switchbacks and snowsheds.
- NHS: National Highway System, a system of major routes
across the US that get partial federal funding
- Pkwy: Parkway
- Purge of 1968: A massive renumbering that the state did
in 1968, in which it got rid of all carrier routes and renumbered
numerous state highways to avoid number duplication with US and
- Ramp Meter:
A traffic signal part way down a freeway onramp that, when operating,
is red part of the time to control the number of vehicles entering the
freeway. The timing of the meter can be set such that it spaces out
cars entering the freeway to smooth out operation of the merge area, or
it can be used to proactively restrict the number of vehicles entering
the freeway to keep the mainline from reaching capacity. Studies have
shown travel time and accidents decrease when meters are used.
- SH x: State Highway x. Generally the same as CO x, but
in very limited circumstances can also refer to Interstate and US
- Spgs: Springs
- Spur: A highway that branches off of the mainline, for
usually a fairly short distance
- Turn Back: The
state taking a stretch of state highway out of its system and turning
authority of it back to a local government. Minnesota term which I've
adopted. "Abandonment" is the official term CDOT uses when it turns a
road over the local control.
Union Pacific Railroad, one of Colorado's two major railroads. Many
maps still label some rail lines as bygone-era companies that no longer
exist such as Southern Pacific and Denver Rio Grande Western, even
though UPRR bought those years ago.
- VMS: Variable message sign, an electronic sign that can
display a variety of messages.
- VPD: Vehicles per day
Sources from Colorado State University Morgan Library (which I used when the site first got going in the late '90s):
- Official Colorado highway maps, CDH/CDOT, 1937, '47, '55,
'72-'76, '80, '84, '86, '87 & '90-'92
- National Atlas of the United States, USGS, 1970
- Colorado/Wyoming map, AAA, 1983
- I-470 - Preliminary Screening Process Report, CDH,
January 30, 1976
- I-470 - Detailed Assessment Report, CDH, September
- Interstate 470 Withdrawal - Substitution Proposal Submitted
to the Secretary of Transportation, Office of Governor Richard
D. Lamm, State of Colorado, July 1977
- The DOT-Mandated Studies on Tolls and Tunnel & Public
Highway Authorities, Kimley-Horn and Associates, Inc., in
association with Decision Economics Inc., for CDOT, 1991
- The High Road, Marion C. Wiley, the Bicentennial
Project of the Division of Highways, CDH, 1976
- Colorado State Highway System - Route Descriptions and
Mileage Statistics, CDH, January 1, 1971, & January 1,
Sources from the Denver Public Library (used in the early 2000s for additional historical info):
- Official Colorado highway maps, CDH/CDOT, 1919, '32, '36, '38,
'39, '46, '47, '49, '50, '54-'58, '60, '61, '63-'68, '70, '76
- Preliminary Report on a North-South Limited Access Highway
Through Denver, to Charles Vail, from Crocker & Ryan
Consulting Engineers, Denver, December 9, 1944
- Commemorating the Opening of the Denver Valley Highway,
CDH, November 23, 1958
- Commemorating the Opening of the East 46th Avenue
Freeway, CDH, September 12, 1964
- Commemorating the Opening of the Colorado-Wyoming Link of
I-25, CDH, October 11, 1964
- Auto Trails Map State of Colorado, Rand McNally, dist.
by Continental Oil, 1923
- Colorado Manual on Uniform Traffic Control Devices,
CDH, 1952, '64 & '68
- Glenwood Canyon: From Origin to Interstate, Conrad F.
Schader, Regio Alta Publications, 1996
Map collection of George Sammeth of Westminster (helped me fill in gaps in research during 2002):
- Official Colorado highway maps, CDH/CDOT, 1970-'94
Sources from other places:
- Official Colorado highway maps, CDOT, 1910s-1999, provided to me in PDF format from CDOT via Dale Sanderson
- Personal copies of CDOT maps, 1997-present
- CDOT online databases, including traffic counts, route descriptions, highway segment information, and
- Miscellaneous CDOT sources, such as press releases and Colorado Transportation Commission meeting information
- Colorado Atlas and Gazetteer, DeLorme, 1995, 2000 and '04
- Mapsco Pierson Guides: Denver Regional; Northern Colorado; and Colorado Springs/Pueblo
- The Roads of Colorado, Shearer Publishing, 1996
- Rand McNally Road Atlas, 1989, '99 & 2000
- National Geographic Road Atlas, 1999
- MapQuest Road Atlas, 2004 and '06
- Google online maps and aerial photos
- Street Atlas USA 4.0 software, DeLorme, 1997
- Colorado/Wyoming maps, AAA, 1994 & '97
- Historical Atlas of Colorado, T.J. Noel, P.F. Mahoney,
and R.E. Stevens, University of Oklahoma Press, 1994
- Various newspaper articles in the Rocky Mountain News, Fort
Collins Coloradoan & Denver Post
- Other Internet sources, be they websites or misc.transport.road
- Information other people have sent me
- My own personal observations from my travelings around the
Last updated 8 June 2014