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PART 1: GENERAL RULES
Speed limit signs inform motorists of speed restrictions established by law or by regulation. The MUTCD. Speed limit types are defined as follows:
LINEAR SPEED LIMITS: A linear speed limit is one that appears along a particular highway, or along a portion of a particular highway.
AREA SPEED LIMITS: An area speed limit is one that applies to all highways within a specific area, except those specifically excluded. The area may be an entire municipality, or only a portion thereof. The defined area may also be the grounds of a school, hospital or other institution.
STATE SPEED LIMIT: The state speed limit is established by the Vehicle and Traffic Law and is applicable on all highways where other speed limits have not been established.
PART 2: ENGINEERING CONSIDERATIONS
Speed limits should be established only where engineering study indicates they are justified and reasonable. Unrealistic regulations are ineffective and should be avoided. Experience has firmly established that posted speed limits have little effect on overall traffic speeds. However, realistic speed limits do provide a sound enforcement basis for citing those who drive at an imprudent speed.
LINEAR SPEED LIMITS: An engineering investigation to determine a linear maximum speed limit should include the following considerations:
- The existing speed pattern, with particular emphasis on the 85th percentile, maximum and ten-mile-per-hour pace speeds.
- Potential traffic conflict due to intersections and roadside development (residences, public buildings, commercial establishments, etc…).
- Traffic volumes, parking practices and pedestrian activity.
- Physical conditions, such as pavement width and condition, shoulder width and condition, grades, alignment, sight distance, etc…
AREA SPEED LIMITS: Evaluations for area speed limits should include the same considerations as for linear speed limits. However, since the specific factors for the highways involved usually vary, a general assessment for the area as a whole must be made.
Within an area, specific highways which warrant higher speed limits than the area in general may be excluded from the area limit, and be subject to a different linear speed limit or the state speed limit.
Specific highways which warrant a lower limit than the general area limit may also be separately regulated on a linear basis. However, since highway conditions themselves generally limit speed, speeds on those highways would naturally be lower, and an exception from the area limit is generally unnecessary.
NUMERICAL VALUES: Maximum speed limits should be established at values appropriate for optimum weather and visibility conditions, and free-flow traffic conditions. Appropriate numerical limits generally approximate off-peak, 85th percentile speeds. Speed limits shall be established in multiples of five miles per hour.
TERMINI AND BOUNDARIES: Speed limits should not extend beyond locations where they are justified. However, care should be taken in selecting linear speed limit termini and area speed limit boundaries to enable effective sign placement.
Termini and boundaries should be selected so that speed limit signs will have adequate visibility and will not conflict with other signs. A speed limit terminus or boundary should be either at an intersection, or at least five hundred feet from the nearest intersection.
SEASONAL AND PART-TIME LIMITS: Such speed limits include recreational and resort area speed limits, part-time speed limits and school speed limits.
- Frequently, speed limits in recreational or resort areas are required only during the tourist season. Such speed limits should be established and posted on a part-time basis.
- Part-time speed limits, applicable for relatively short periods (for example, two hours per day or two days per week), are permissible. Such speed limits should be posted with variable message signs supplemented by flashing beacons.
- School speed limits are a special type of part-time speed limit.
MAXIMUM SPEED LIMIT SIGNS:
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