Summary of State Speed Laws - NHTSA

JURISDICTION: IDAHO
General References: Idaho Code (General Laws of Idaho Annotated), Idaho
Infraction (Court) Rules and Idaho Administrative Code
(IDAPA)
Basis for a Speed Law Violation:
SPEED 2005
Basic Speed Rule: No person shall drive a vehicle at a speed
greater than is reasonable and prudent under the conditions
and having regard to the actual and potential hazards then
existing. §49-654(1)
Statutory Speed Limit: 75 mph on interstate highways §49-654(2)(c)
See Other below. 65 mph on Stats highways §49-654(2)(d)
55 mph in other locations §49-654(2)(e)
35 mph in a residential, business, or urban districts §49-
654(2)(a) and (b)
Posted (Maximum) Speed Limit: I. Based on engineering and traffic investigations, the State
may increase or decrease the above speed limits. 135 However,
no maximum posted speed limit can exceed either 75 mph for
interstate highways or 65 mph for other State highways. §49-
201(4)
II. For highways within its jurisdiction, a local government,
based on engineering and traffic investigations, may (1)
decrease the speed limit in a residential, business or urban
districts or (2) increase the speed limits above the statutory
limit for an urban district but not >65 mph on arterial
highways. §§49-207(2) and 49-208(1)(i)
III. Local authorities within their jurisdictions may establish
speed limits for public parks. §49-208(1)(e)
IV. Local authorities may lower the speed limits on those
portions of State highways that pass through residential or
business districts within their jurisdiction. §49-201(4). These
speed limits must be less than the maximum speed limits
established by the State. §49-208(w)
Minimum Speed Limit: I. No person shall drive a motor vehicle at such slow speed as
to impede the normal and reasonable movement of traffic
except when reduced speed is necessary for safe operation or
in compliance with the law. §49-655
II. A person driving at less than the normal speed of traffic
shall drive in the right-hand lane available for
135 This includes the establishment of different highway speed limits (1) for different types of vehicles (e.g., persons who
operate certain types of trucks may be required to drive these vehicles at a slower speed than those who operate other types
of motor vehicles), (2) at different times of the day, (3) for various weather conditions or (4) for other factors bearing on
safe speeds. §49-201(4)
66