Colo. Rev. Stat. § 42-4-1101 : VEHICLES AND TRAFFIC —REGULATION OF VEHICLES AND TRAFFIC — Regulation of Vehicles and Traffic — SPEED REGULATIONS —4-1101 - Speed limits

(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.

C.R.S. § 42-4-1101

L. 94: Entire title amended with relocations, p. 2363, § 1, effective 1/1/1995. 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.

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.

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".