1. Subject to the provisions of section 39-09-01 and except in those instances when a lower speed is specified in this chapter, it presumably is lawful for the driver of a vehicle to drive the same at a speed not exceeding: a. Twenty miles [32.19 kilometers] an hour when approaching within fifty feet [15.24 meters] of a grade crossing of any steam, electric, or street railway when the driver's view is obstructed. A driver's view is deemed to be obstructed when at any time during the last two hundred feet [60.96 meters] of the driver's approach to such crossing, the driver does not have a clear and uninterrupted view of such railway crossing and of any traffic on such railway for a distance of four hundred feet [121.92 meters] in each direction from such crossing.
b. Twenty miles [32.19 kilometers] an hour when passing a school during school recess or while children are going to or leaving school during opening or closing hours, unless a lower speed is designated or posted by local authorities. c. Twenty miles [32.19 kilometers] an hour when approaching within fifty feet [15.24 meters] and in traversing an intersection of highways when the driver's view is obstructed. A driver's view is deemed to be obstructed when at any time during the last fifty feet [15.24 meters] of the driver's approach to such intersection, the driver does not have a clear and uninterrupted view of such intersection and of the traffic upon all of the highways entering such intersection for a distance of two hundred feet [60.96 meters] from such intersection. d. Twenty miles [32.19 kilometers] an hour when the driver's view of the highway ahead is obstructed within a distance of one hundred feet [30.48 meters]. e. Twenty-five miles [40.23 kilometers] an hour on any highway in a business district or in a residence district or in a public park, unless a different speed is designated and posted by local authorities. f. Fifty-five miles [88.51 kilometers] an hour on gravel, dirt, or loose surface highways, and on paved two-lane county and township highways if there is no speed limit posted, unless otherwise permitted, restricted, or required by conditions. g. Sixty-five miles [104.61 kilometers] an hour on paved two-lane highways if posted for that speed, unless otherwise permitted, restricted, or required by conditions. h. Seventy miles [112.65 kilometers] an hour on paved and divided multilane highways, unless otherwise permitted, restricted, or required by conditions. i. Eighty miles [128.75 kilometers] an hour on access-controlled, paved and divided, multilane interstate highways, unless otherwise permitted, restricted, or required by conditions. 2. The director may designate and post special areas of state highways where lower speed limits apply. Differing limits may be established for different times of the day within highway construction zones which are effective when posted upon appropriate fixed or variable speed limit signs. 3. The director may designate variable speed limit adjustment zones along the state highway system. The department may install variable speed limit signs in a variable speed limit adjustment zone. In each variable speed limit adjustment zone the director, in coordination with the superintendent of the highway patrol, may use real time intelligent transportation systems to adjust the speed limit when a speed limit adjustment would provide for the safe and efficient movement of motor vehicles. 4. Except as provided by law, a person may not drive a vehicle on a highway at a speed that is unsafe or at a speed exceeding the speed limit prescribed by law or established pursuant to law. 5. In charging a violation of the provisions of this section, the complaint must specify the speed at which the defendant is alleged to have driven and the speed which this section prescribes is prima facie lawful at the time and place of the alleged offense.
39-09-03. When local authorities may or shall alter maximum speed - Limits - Signs posted. 1. Whenever local authorities in their respective jurisdictions, on the basis of an engineering and traffic investigation, determine that the maximum speed permitted under this title is greater or less than is reasonable and safe under the conditions found to exist upon a highway or part of a highway, the local authority may determine and declare a reasonable and safe maximum limit thereon which: a. Decreases the limit at intersections; b. Increases the limit within an urban district but not to more than fifty-five miles [88.51 kilometers] per hour; or c. Decreases the limit outside an urban district. 2. Local authorities in their respective jurisdictions shall determine by an engineering and traffic investigation the proper maximum speed for arterial streets and shall declare a
reasonable and safe maximum limit thereon which may be greater or less than the maximum speed permitted under this chapter for an urban district. 3. Any altered limit established as hereinabove authorized shall be effective at all times or during hours of darkness or at other times as may be determined when appropriate signs giving notice thereof are erected upon such street or highway. 4. Any alteration of maximum limits on state highways or extensions thereof in a municipality by local authorities may not be effective until such alteration has been approved by the director. 5. Not more than six such alterations as hereinabove authorized may be made per mile [1.61 kilometers] along a street or highway, except in the case of reduced limits at intersections, and the difference between adjacent limits may not be more than ten miles [16.09 kilometers] per hour.