Wyoming Administrative Code › Agency 045 - Transportation, Dept. of › Sub-Agency 0003 - General Agency, Board or Commission Rules › Chapter 30 - PROCEDURES FOR LOCALLY ESTABLISHING SPEED LIMITS › Appendix I - Procedures for Establishing Local Authority Set Speed Limits on Wyoming Paved Roads › Section 1.5 - DETERMINATION OF APPROPRIATE SPEED LIMIT

Current through July 13, 2024
(1)
Speed limits and speed
					 zoning can be controversial. Engineers, public safety officials, and others
					 involved in setting and enforcing speed limits may disagree on the appropriate
					 balance between safety and road-user convenience that should prevail on
					 particular road segments, considering conditions of topography, weather,
					 adjacent activities, and traffic. Motorists, other road users, and roadway
					 neighbors have their own perspectives on this balance and may not abide by the
					 professionals' judgments.
(2)
The criteria to a set a
					 speed limit generally consider such factors as the physical features of the
					 roadway, crash experience, traffic characteristics and control (for example,
					 signals and other control devices), and the length of the roadway segment under
					 consideration (speed-limit changes should not be too frequent or applied to
					 very short road segments).
(3)
If the regulation of
					 speed is to be effective, the posted limit must be generally consistent with
					 speeds that drivers feel are safe and proper. Enforcement is widely recognized
					 to be crucial to the success of speed limits as a means for making roads safer.
					 If law enforcement officers and the courts are confident that speed limits have
					 been developed on a reasonable basis, their enforcement of the limits will be
					 more effective. Generally, speed limits should be set at levels that are
					 self-enforcing so that law enforcement officials can concentrate their efforts
					 on the worst offenders.
(4)
One of the factors
					 considered very important for setting a speed limit is the prevailing vehicle
					 speed. The
Manual on Uniform Traffic Control Devices (MUTCD)
is quite explicit, stating that when a speed limit within a speed zone is
					 posted, it should be within 5 mph of the 85th-percentile speed of free-flowing
					 traffic. The Speed Study output sheets show the recommended speed limit based
					 on this criterion.
(5)
The
					 MUTCD
indicates other factors may also influence the appropriate speed
					 limit, including roadway characteristics such as shoulder condition, grade,
					 alignment, and sight distance; the pace; roadside development and environment;
					 parking practices and pedestrian activity; and reported crash experience for at
					 least a 12-month period.
(6)
These other factors may
					 be used to justify a speed limit somewhat lower than the 85th-percentile speed,
					 but in no circumstance should the speed limit be posted below the
					 50th-percentile speed or lower limit of the 10-mph pace.
(7)
In cases where the speed
					 limit is posted below the 85th-percentile speed based on the other factors, the
					 speed limit sign serves to remind motorists that conditions in the area are
					 such that the speed reduction is reasonable. Proper use of speed limit signs
					 instills confidence in the minds of drivers that the information on the speed
					 limit sign is accurate and not simply a desire on the part of a policy maker to
					 reduce speed arbitrarily for emotional or political reasons.