Iowa Code » Chapter 321 — MOTOR VEHICLES AND LAW OF THE ROAD
Iowa Code

Iowa Code § 321.285 (2026)

Speed restrictions

✓ current as of July 2026
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1. Any person driving a motor vehicle on a highway shall drive the same at a careful and prudent speed not greater than nor less than is reasonable and proper, having due regard to the traffic, surface, and width of the highway and of any other conditions then existing, and no person shall drive any vehicle upon a highway at a speed greater than will permit the person to bring it to a stop within the assured clear distance ahead, such driver having the right to assume, however, that all persons using said highway will observe the law. 2. a. Unless otherwise provided by this section, or except as posted pursuant to sections 262.68, 321.236, subsection 5, section 321.288, subsection 2, paragraph “f”, sections 321.289, 321.290, 321.293, 321.295, and 461A.36, the following shall be the lawful speed and any speed in excess thereof shall be unlawful: (1) Twenty miles per hour in any business district. (2) Twenty-five miles per hour in any residence or school district. (3) Forty-five miles per hour in any suburban district. b. Each school district as defined in section 321.1, subsection 70, shall be marked by\n\nTue Dec 09 22:17:00 2025 Iowa Code 2026, Chapter 321 (137, 2) §321.285, MOTOR VEHICLES AND LAW OF THE ROAD 192\n\ndistinctive signs as provided by the current manual of uniform traffic control devices adopted by the department and placed on the highway at the limits of such school district. 3. Unless otherwise provided in this section or by other speed restrictions, the speed limit for all vehicular traffic shall be fifty-five miles per hour. 4. A reasonable and proper speed is required, but not greater than fifty-five miles per hour at any time between sunrise and sunset, and not greater than fifty miles per hour at any time between sunset and sunrise, on secondary roads unless such roads are surfaced with concrete or asphalt or a combination of both, in which case the speed limits shall be the same as provided in subsection 3. When the board of supervisors of any county shall determine upon the basis of an engineering and traffic investigation that the speed limit on any secondary road is greater than is reasonable and proper under the conditions found to exist at any intersection or other place or upon any part of a secondary road, the board shall determine and declare a reasonable and proper speed limit at the intersection or other part of the secondary road. The speed limits as determined by the board of supervisors shall be effective when appropriate signs giving notice of the speed limits are erected by the board of supervisors at the intersection or other place or part of the highway. 5. a. Notwithstanding any other speed restrictions, the speed limit for all vehicular traffic on fully controlled-access, divided, multilaned highways is sixty-five miles per hour. However, the speed limit for all vehicular traffic on highways that are part of the interstate road system, as defined in section 306.3, is seventy miles per hour. The department may establish a speed limit of sixty-five miles per hour on certain divided, multilaned highways not otherwise described in this paragraph. b. The department, on its own motion or in response to a recommendation of a metropolitan or regional planning commission or council of governments, may establish a lower speed limit on a highway described in this subsection. c. For the purposes of this subsection, “fully controlled-access highway” means a highway that gives preference to through traffic by providing access connections with selected public roads only and by prohibiting crossings at grade or direct private driveway connections. d. A minimum speed may be established by the department on the highways referred to in this subsection if warranted by engineering and traffic investigations. e. (1) A vehicle, device, implement, or conveyance incapable of attaining and maintaining a speed of forty miles per hour shall be prohibited from using the interstate road system. (2) This paragraph does not apply to an implement of husbandry that a person is authorized to operate on the segment of United States highway 65, and state highway 5, including where the highway designations overlap, between the highway’s intersection with United States highway 6 and the highway’s intersection with United States highway 69, or farther west if authorized by the department, prior to the date that segment of highway is designated a part of the interstate road system, if the segment of highway is designated a part of the interstate road system. The department may authorize an implement of husbandry to be operated on a segment of the highway described above farther west beyond the intersection with United States highway 69. This subparagraph is repealed on the date an alternative route for implements of husbandry is developed, deemed suitable by the department of transportation in consultation with the department of agriculture and land stewardship, and opened for traffic to bypass the segment of the interstate road system described in this subparagraph. The department of transportation shall notify the Iowa Code editor on that date. 6. Notwithstanding any other speed restrictions, a self-propelled implement of husbandry equipped with flotation tires that is designed to be loaded and operated in the field and used exclusively for the application of organic or inorganic plant food materials, agricultural limestone, or agricultural chemicals shall not be operated on a highway at a speed in excess of thirty-five miles per hour. 7. Notwithstanding any other speed restrictions, the speed limit for all vehicular traffic on a street or highway on which a cattle guard is installed pursuant to section 314.30 is fifteen miles per hour between the point at which the cattle guard is installed and the point at which the street or highway terminates in a dead end. 8. A person who violates this section for excessive speed in violation of a speed limit

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Tue Dec 09 22:17:00 2025 Iowa Code 2026, Chapter 321 (137, 2) 193 MOTOR VEHICLES AND LAW OF THE ROAD, §321.290\n\ncommits a simple misdemeanor punishable as a scheduled violation under section 805.8A, subsection 5. A person who operates a school bus at a speed which exceeds a limit established under this section by ten miles per hour or less commits a simple misdemeanor punishable as a scheduled violation under section 805.8A, subsection 10. A person who violates any other provision of this section commits a simple misdemeanor. [S13, §1571-m19, -m20; C24, 27, 31, 35, §5029, 5030; C39, §5023.01; C46, 50, 54, 58, 62, 66, 71, 73, 75, 77, 79, 81, §321.285] 87 Acts, ch 120, §2; 93 Acts, ch 47, §3 – 7; 94 Acts, ch 1173, §15; 96 Acts, ch 1126, §5; 96 Acts, ch 1191, §1; 2005 Acts, ch 165, §1; 2007 Acts, ch 143, §15; 2009 Acts, ch 133, §119; 2010 Acts, ch 1140, §8; 2012 Acts, ch 1083, §1; 2013 Acts, ch 90, §81; 2017 Acts, ch 29, §95; 2018 Acts, ch 1041, §82; 2018 Acts, ch 1118, §2, 3; 2025 Acts, ch 118, §2, 4 Referred to in §321.233, 321.236, 321.291, 321.292, 321.293, 331.362, 707.6A, 723.4, 805.8A(5)(a), 805.8A(10) Speed limits at regents institutions, see §262.68 Speeding violations by implements of husbandry, see §321.383 Speed limits in state parks and preserves, see §461A.36 2025 amendment to subsection 5, paragraph e applies to the segment of the highway known as United States highway 65, and state highway 5, including where the highway designations overlap, on July 1, 2025, and shall apply to that segment of the highway thereafter regardless of whether the highway’s designation is subsequently changed; 2025 Acts, ch 118, §4 Subsection 5, paragraph e amended\n\n 321.286 and 321.287 Reserved.

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Notes of Decisions
Cited in 123 cases (5 in the last 5 years), 1947–2025 · leading case: Rickie Rilea & Timothy Riley v. Iowa Dep't of Transp., 919 N.W.2d 380 (Iowa 2018).
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Rickie Rilea & Timothy Riley v. Iowa Dep't of Transp., 919 N.W.2d 380 (Iowa 2018). · cites it 11× “See Iowa Code § 321.285 (5). But it is a grant of authority to the IDOT to set speed limits, not to enforce them with stops, citations, and arrests.”
City of Sioux City v. Michael Jon Jacobsma, 862 N.W.2d 335 (Iowa 2015). · cites it 7× “Under section 4(a), the civil penalty assessed is equivalent to the scheduled fine, including all surcharges and costs, established by Iowa Code section 321.285 for excessive speed over the posted speed limit.”
State of Iowa v. Scottize Danyelle Brown, 930 N.W.2d 840 (Iowa 2019). · cites it 2× “§ 321.285(1), or at a speed that “impede[s] or block[s] the normal and reasonable movement of traffic,” id.”
State v. Coppes, 78 N.W.2d 10 (Iowa 1956). · cites it 15× “That the statute (section 321.285, Iowa Code of 1954) upon which the information is based so far as it undertakes to create a criminal offense is void in that the statute does not expressly forbid or require any act except by implication.”
City of Davenport v. Seymour, 755 N.W.2d 533 (Iowa 2008). · cites it 4× “Iowa Code §§ 321.285 , *540 321.256. Infractions for speeding and violating traffic signals are generally considered simple misdemeanors.”
City of Des Moines v. Iowa Dep't of Transp. & Iowa Transp. Comm'n, 911 N.W.2d 431 (Iowa 2018). · cites it 4× “Could the IDOT issue a rule banning the practice on the ground that it has "jurisdiction and control" over these roads? Clearly not.”
Reich v. Miller, 151 N.W.2d 605 (Iowa 1967). · cites it 14× “The important question this appeal presents is whether defendant’s alleged violation of the assured-clear-distance rule set out in section 321.285, Codes 1958, 1962, was properly submitted to the jury as a charge of negligence against him by plaintiff, driver of a car which came…”
Jones v. Blair, 387 N.W.2d 349 (Iowa 1986). · cites it 6× “288(3); 3) driving at a greater speed than would permit stopping within an assured clear distance, Iowa Code section 321.285; 4) following too closely, Iowa Code section 321.”
State v. Klawonn, 609 N.W.2d 515 (Iowa 2000). · cites it 4× “See Iowa Code §§ 321.285 , 321.482, and 805.8(2) (1997).”
Martin v. Cafer, 138 N.W.2d 71 (Iowa 1965). · cites it 12× “Plaintiff again offered the accident report in evidence as proof of the arrest of defendant for violation of section 321.285, Code, 1962. His stated purpose was to connect up evidence of defendant's plea of guilty to such charge.”
Schmitt v. Clayton Cnty., 284 N.W.2d 186 (Iowa 1979). · cites it 8× “We conclude that violation of the duty to travel at a reasonable and proper speed under the circumstances, mandated by § 321.285, The Code 1973, constitutes negligence per se and that the jury should have been so instructed.”
Bergeson v. Pesch, 117 N.W.2d 431 (Iowa 1962). · cites it 7× “Conviction * * * upon three charges of any speed restriction violation under the provisions of sections 321.285 to 321.287, inclusive, committed within a period of twelve months.”
Show all 123 citing cases →
— Iowa Code § 321.285(1) — 3 cases
State of Iowa v. Scottize Danyelle Brown, 930 N.W.2d 840 (Iowa 2019). “§ 321.285(1), or at a speed that “impede[s] or block[s] the normal and reasonable movement of traffic,” id.”
State of Iowa v. Kyra Rose Bauler (Iowa 2024).
State of Iowa v. Scottize Danyelle Brown (Iowa 2019).
— Iowa Code § 321.285(2) — 1 case
Walker v. Sedrel, 149 N.W.2d 874 (Iowa 1967).
— Iowa Code § 321.285(2)(a) — 1 case
State of Iowa v. Terry Joseph Schmitz (Iowa Ct. App. 2025).
— Iowa Code § 321.285(2)(a)(1) — 1 case
State of Iowa v. Terry Joseph Schmitz (Iowa Ct. App. 2025).
— Iowa Code § 321.285(2)(a)(2) — 1 case
State of Iowa v. Terry Joseph Schmitz (Iowa Ct. App. 2025).
— Iowa Code § 321.285(2)(a)(3) — 1 case
State of Iowa v. Terry Joseph Schmitz (Iowa Ct. App. 2025).
— Iowa Code § 321.285(3) — 1 case
State of Iowa v. Terry Joseph Schmitz (Iowa Ct. App. 2025).
— Iowa Code § 321.285(4) — 2 cases
City of Janesville v. McCartney, 326 N.W.2d 785 (Iowa 1982).
Mass v. Mesic, 142 N.W.2d 389 (Iowa 1966).
— Iowa Code § 321.285(5) — 2 cases
City of Des Moines v. Iowa Dep't of Transp. & Iowa Transp. Comm'n, 911 N.W.2d 431 (Iowa 2018). “Could the IDOT issue a rule banning the practice on the ground that it has "jurisdiction and control" over these roads? Clearly not.”
City of Des Moines v. Iowa DOT (Iowa 2018).
— Iowa Code § 321.285(7) — 3 cases
Vogel v. Reeg, 225 N.W.2d 132 (Iowa 1975).
Burns v. Rodriquez, 448 N.W.2d 673 (Iowa Ct. App. 1989).
State of Iowa v. Bounmy Bounmy (Iowa Ct. App. 2017).
— Iowa Code § 321.285(8) — 1 case
State of Iowa v. Kevin Dwayne Woods, Jr. (Iowa 2025).
— Iowa Code § 321.285(l) — 1 case
State v. Philo, 697 N.W.2d 481 (Iowa 2005).
Annotations are extracted automatically from the opinions in the Syfert caselaw corpus and ranked by authority, recency, and treatment. Dots show Syfertize treatment of the citing case itself.