(a) Establishment. A hazardous grade speed limit may be established under 75 Pa.C.S. § 3365(c) (relating to special speed limitations) if an engineering and traffic study establishes the need for all vehicles or vehicles having a gross weight in excess of a designated weight to be limited to a maximum speed on a downgrade.

1. (1) The designated weight should be 26,000 pounds unless the engineering and traffic study determines that a different weight should be used.
2. (2) When a hazardous-grade speed limit is established, it should be consistent with the speed that similar vehicles can climb the hill or other Department-approved methodology, except that a hazardous-grade speed limit should not be greater than the lowest advisory speed or legal speed limit either on the hill or at the base of the hill.

3. (3) A hazardous-grade speed limit may be established when one or more of the following conditions exist:

   1. (i) The length of grade exceeds the value set forth in the following table:

      	Length of Grade (feet)
      Average Grade (percent)	Condition A*	Condition B**
      -3	20,000	—
      -4	8,000	16,000
      -5	5,000	10,000
      -6	3,000	6,000
      -7	2,000	4,000
      -8	1,800	3,600
      -10	1,500	3,000
      -12	1,250	2,500
      -15	1,000	2,000

      * Condition A applies if vehicles are required to stop or reduce speed at or before the bottom of the hill or if there is an urbanized area at the base of the hill.

      ** Condition B pertains to all other locations.

   2. (ii) A crash has occurred on the downgrade that can be attributed to the speed of a vehicle having a gross weight in excess of the designated weight.
   3. (iii) A verified report has been received during the past 3 years of an operator losing control of a vehicle on the grade, and the vehicle is a type having a gross weight in excess of the designated weight.

(b) Posting. A hazardous grade speed limit shall be posted with traffic-control devices as follows:

1. (1) A Reduced Speed (

   ) Ahead Sign (R2-5), advising of the maximum hazardous grade speed limit, with a Truck Marker (M4-4), or other marker as applicable, mounted directly above the Reduced Speed ( ) Ahead Sign (R2-5), shall be placed on the right side of the highway at a distance of 500 to 1,000 feet before the hazardous grade speed limit, except that this advance sign is not required if the hazardous grade speed limit begins at a vehicle pull-off where all applicable vehicles are required to stop.

2. (2) A Trucks Over (

   ) Lbs. Speed Sign (R2-2-1), or other sign as applicable, shall be erected at the beginning of the hazardous grade speed zone and at intervals not greater than 1/4 mile throughout the zone.

3. (3) A Trucks Over (

   ) Lbs. Speed Sign (R2-2-1), or other sign as applicable, with an End Sign (R2-10) mounted above the Trucks Over ( ) Lbs. Speed Sign (R2-2-1) or other sign, shall be installed at the end of the hazardous grade speed limit.