(1) No person shall drive a vehicle on a highway at a speed greater than is reasonable and prudent under the conditions then existing.
(2) Except when a special hazard exists that requires a lower speed, the following speeds shall be lawful:
(a) Twenty miles per hour on narrow, winding mountain highways or on blind curves;
(b) Twenty-five miles per hour in any business district, as defined in section 42-1-102 (11);
(c) Thirty miles per hour in any residence district, as defined in section 42-1-102 (80);
(d) Forty miles per hour on open mountain highways;
(e) Forty-five miles per hour for all single rear axle vehicles in the business of transporting trash that exceed twenty thousand pounds, where higher speeds are posted, when said vehicle is loaded as an exempted vehicle pursuant to section 42-4-507 (3);
(f) Fifty-five miles per hour on other open highways which are not on the interstate system, as defined in section 43-2-101 (2), C.R.S., and are not surfaced, four-lane freeways or expressways;
(g) Sixty-five miles per hour on surfaced, four-lane highways which are on the interstate system, as defined in section 43-2-101 (2), C.R.S., or are freeways or expressways;
(h) Any speed not in excess of a speed limit designated by an official traffic control device.
(3) No driver of a vehicle shall fail to decrease the speed of such vehicle from an otherwise lawful speed to a reasonable and prudent speed when a special hazard exists with respect to pedestrians or other traffic or by reason of weather or highway conditions.
(4) Except as otherwise provided in paragraph (c) of subsection (8) of this section, any speed in excess of the lawful speeds set forth in subsection (2) of this section shall be prima facie evidence that such speed was not reasonable or prudent under the conditions then existing. As used in this subsection (4), prima facie evidence means evidence which is sufficient proof that the speed was not reasonable or prudent under the conditions then existing, and which will remain sufficient proof of such fact, unless contradicted and overcome by evidence bearing upon the question of whether or not the speed was reasonable and prudent under the conditions then existing.
(5) In every charge of violating subsection (1) of this section, the complaint, summons and complaint, or penalty assessment notice shall specify the speed at which the defendant is alleged to have driven and also the alleged reasonable and prudent speed applicable at the specified time and location of the alleged violation.
(6) The provisions of this section shall not be construed to relieve the party alleging negligence under this section in any civil action for damages from the burden of proving that such negligence was the proximate cause of an accident.
(7) Notwithstanding paragraphs (a), (b), and (c) of subsection (2) of this section, any city or town may by ordinance adopt absolute speed limits as the maximum lawful speed limits in its jurisdiction, and such speed limits shall not be subject to the provisions of subsection (4) of this section.
(8) (a) (Deleted by amendment, L. 96, p. 578, � 2, effective May 25, 1996.)
(b) Notwithstanding any other provisions of this section, no person shall drive a vehicle on a highway at a speed in excess of a maximum lawful speed limit of seventy-five miles per hour.
(c) The speed limit set forth in paragraph (b) of this subsection (8) is the maximum lawful speed limit and is not subject to the provisions of subsection (4) of this section.
(d) State and local authorities within their respective jurisdictions shall not authorize any speed limit which exceeds seventy-five miles per hour on any highway.
(e) The provisions of this subsection (8) are declared to be matters of both local and statewide concern requiring uniform compliance throughout the state.
(f) In every charge of a violation of paragraph (b) of this subsection (8), the complaint, summons and complaint, or penalty assessment notice shall specify the speed at which the defendant is alleged to have driven and also the maximum lawful speed limit of seventy-five miles per hour.
(g) Notwithstanding any other provision of this section, no person shall drive a low-power scooter on a roadway at a speed in excess of forty miles per hour. State and local authorities shall not authorize low-power scooters to exceed forty miles per hour on a roadway.
(9) The conduct of a driver of a vehicle which would otherwise constitute a violation of this section is justifiable and not unlawful when:
(a) It is necessary as an emergency measure to avoid an imminent public or private injury which is about to occur by reason of a situation occasioned or developed through no conduct of said driver and which is of sufficient gravity that, according to ordinary standards of intelligence and morality, the desirability and urgency of avoiding the injury clearly outweigh the desirability of avoiding the consequences sought to be prevented by this section; or
(b) With respect to authorized emergency vehicles, the applicable conditions for exemption, as set forth in section 42-4-108, exist.
(10) The minimum requirement for commission of a traffic infraction or misdemeanor traffic offense under this section is the performance by a driver of prohibited conduct, which includes a voluntary act or the omission to perform an act which said driver is physically capable of performing.
(11) It shall not be a defense to prosecution for a violation of this section that:
(a) The defendant's conduct was not performed intentionally, knowingly, recklessly, or with criminal negligence; or
(b) The defendant's conduct was performed under a mistaken belief of fact, including, but not limited to, a mistaken belief of the defendant regarding the speed of the defendant's vehicle; or
(c) The defendant's vehicle has a greater operating or fuel-conserving efficiency at speeds greater than the reasonable and prudent speed under the conditions then existing or at speeds greater than the maximum lawful speed limit.
(12) (a) A violation of driving one to twenty-four miles per hour in excess of the reasonable and prudent speed or in excess of the maximum lawful speed limit of seventy-five miles per hour is a class A traffic infraction.
(b) A violation of driving twenty-five or more miles per hour in excess of the reasonable and prudent speed or in excess of the maximum lawful speed limit of seventy-five miles per hour is a class 2 misdemeanor traffic offense; except that such violation within a maintenance, repair, or construction zone, designated pursuant to section 42-4-614, is a class 1 misdemeanor traffic offense.
(c) A violation under subsection (3) of this section is a class A traffic infraction.
Source: L. 94: Entire title amended with relocations, p. 2363, � 1, effective January 1, 1995. L. 96: (2)(f), (2)(g), (8)(a), (8)(b), (8)(c), (8)(d), (8)(f), and (12) amended, p. 578, � 2, effective May 25. L. 2003: (2)(e) amended, p. 717, � 1, effective August 6. L. 2008: (12) amended, p. 2082, � 7, effective June 3. L. 2009: (8)(g) added, (HB 09-1026), ch. 281, p. 1277, � 54, effective October 1.
Editor's note: This section is similar to former � 42-4-1001 as it existed prior to 1994, and the former � 42-4-1101 was relocated to � 42-4-1201.
Cross references: Section 1 of chapter 412, Session Laws of Colorado 2008, provides that the act amending subsection (12) shall be known and may be cited as the Charles Mather Highway Safety Act.
42-4-1102. Altering of speed limits - department to study rural state highways and increase speed limits - definitions. (1) (a) Whenever the department of transportation determines upon the basis of a traffic investigation or survey or upon the basis of appropriate design standards and projected traffic volumes in the case of newly constructed highways or segments thereof that any speed specified or established as authorized under sections 42-4-1101 to 42-4-1104 is greater or less than is reasonable or safe under the road and traffic conditions at any intersection or other place or upon any part of a state highway under its jurisdiction, said department shall determine and declare a reasonable and safe speed limit thereat which shall be effective when appropriate signs giving notice thereof are erected at such intersection or other place or upon the approaches thereto; except that no speed limit in excess of seventy-five miles per hour shall be authorized by said department.
(b) Repealed.
(2) Whenever county or municipal authorities, within their respective jurisdictions, determine upon the basis of a traffic investigation or survey and, for residential neighborhoods, after additional optional consideration of road characteristics, current and future development, environmental factors, parking practices, pedestrian and bicycle activity in the vicinity, and crash statistics from the most recent year, or upon the basis of appropriate design standards and projected traffic volumes in the case of newly constructed highways or segments thereof, that any speed specified or established as authorized under sections 42-4-1101 to 42-4-1104 is greater or less than is reasonable or safe under the road and traffic conditions at an intersection or other place or upon any part of a street or highway in its jurisdiction, the local authority shall determine and declare a reasonable and safe speed limit that is effective when appropriate signs giving notice thereof are erected at the intersection or other place or upon the approaches thereto. A local authority shall not alter the basic rules set forth in section 42-4-1101 (1) or authorize by resolution or ordinance a speed in excess of seventy-five miles per hour.
(3) Local municipal authorities within their respective jurisdictions shall determine upon the basis of a traffic investigation or survey the proper speed for all arterial streets and shall declare a reasonable and safe speed limit thereon which may be greater or less than the speed specified under section 42-4-1101 (2)(b) or (2)(c). Such speed limit shall not exceed seventy-five miles per hour and shall become effective when appropriate signs are erected giving notice thereof. For purposes of this subsection (3), an arterial street means any United States or state-numbered route, controlled-access highway, or other major radial or circumferential street or highway designated by local authorities within their respective jurisdictions as part of a major arterial system of streets or highways.
(3.5) Repealed.
(4) No alteration of speed limits on state highways within cities, cities and counties, and incorporated towns is effective until it has been approved in writing by the department of transportation. Upon the request of any incorporated city or town, the department of transportation shall conduct any traffic investigation or survey that is deemed to be warranted for determination of a safe and reasonable speed limit on any street or portion thereof that is a state highway. In conducting such a traffic investigation, the department may receive and consider traffic and engineering data provided by the city or county engineer of any requesting local government that will be impacted by a proposed alteration of speed limits. Any speed limit so determined by the department becomes effective when declared by the local authority and made known by official signs conforming to the state traffic control manual.
(5) Whenever the department of transportation or local authorities, within their respective jurisdictions, determine upon the basis of a traffic investigation or survey that a reduced speed limit is warranted in a school or construction area or other place during certain hours or periods of the day when special or temporary hazards exist, the department or the concerned local authority may erect or display official signs of a type prescribed in the state traffic control manual giving notice of the appropriate speed limit for such conditions and stating the time or period the regulation is effective. When such signs are erected or displayed, the lawful speed limit at the particular time and place shall be that which is then indicated upon such signs; except that no such speed limit shall be less than twenty miles per hour on a state highway or other arterial street as defined in subsection (3) of this section nor less than fifteen miles per hour on any other road or street, nor shall any such reduced speed limit be made applicable at times when the special conditions for which it is imposed cease to exist. Such reduced speed limits on streets which are state highways shall be subject to the written approval of the department of transportation before becoming effective.
(6) In its discretion, a municipality, by ordinance, or a county, by resolution of the board of county commissioners, may impose and enforce stop sign regulations and speed limits, not inconsistent with the provisions of sections 42-4-1101 to 42-4-1104, upon any way which is open to travel by motor vehicles and which is privately maintained in mobile home parks, when appropriate signs giving notice of such enforcement are erected at the entrances to such ways. Unless there is an agreement to the contrary, the jurisdiction ordering the regulations shall be responsible for the erection and maintenance of the signs.
(7) Any powers granted in this section to county or municipal authorities may be exercised by such authorities or by any municipal officer or employee who is designated by ordinance to exercise such powers.
(8) The department of transportation shall not set a speed limit on interstate 70 for commercial vehicles or any other motor vehicle that differs from the highest authorized speed for any other type of motor vehicle on the same portion of a highway by more than twenty-five miles per hour.
(9) For purposes of this section, residential neighborhood has the same meaning as set forth in section 42-4-110.5 (2)(g)(II).
Source: L. 94: Entire title amended with relocations, p. 2366, � 1, effective January 1, 1995. L. 95: (3) amended, p. 956, � 16, effective May 25. L. 96: (1), (2), and (3) amended, p. 579, � 3, effective May 25. L. 2010: (8) added, (SB 10-196), ch. 333, p. 1534, � 1, effective July 1. L. 2014: (4) amended, (SB 14-146), ch. 141, p. 486, � 1, effective May 2. L. 2018: (2) amended and (9) added, (HB 18-1191), ch. 156, p. 1098, � 1, effective August 8. L. 2020: (3.5) added, (HB 20-1178), ch. 90, p. 361, � 1, effective September 14.
Editor's note: (1) This section is similar to former � 42-4-1002 as it existed prior to 1994, and the former � 42-4-1102 was relocated to � 42-4-1202.
(2) Subsection (1)(b)(II) provided for the repeal of subsection (1)(b), effective July 1, 1998. (See L. 96, p. 579.)
(3) Subsection (3.5)(e) provided for the repeal of subsection (3.5), effective July 1, 2022. (See L. 2020, p. 361.)