Minn. R. Part 8820.9981

Current through Register Vol. 48, No. 51, June 17, 2024

Part 8820.9981 - MINIMUM DESIGN STANDARDS: NATURAL PRESERVATION ROUTES, DESIGNATED NATIONAL FOREST HIGHWAYS WITHIN NATIONAL FORESTS, AND STATE PARK ACCESS ROADS WITHIN STATE PARKS; NEW OR RECONSTRUCTION PROJECTS

Subpart 1.Type I route.

New or reconstruction projects for type I natural preservation routes, designated national forest highways within national forests, and state park access roads within state parks must meet or exceed the minimum dimensions indicated in the following design chart.

Surface Type	Design Speed	Lane Width	Shoulder Width	Inslope	Clear Zone	Design Strength	Bridge to Remain
	(mph)	(feet)	(feet)	(rise: run)	(feet)	(tons)	(feet)
			(a)	(b)	(c)		(d)
Aggregate	30	11	1	1:3	3		22
Paved	30	11	2	1:3	9	9	22

(a) If the route has scenic vistas that will require parking vehicles along the shoulder, widening the shoulder at these locations is acceptable. The designer will provide a four-foot paved shoulder if the route is a popular bicycle route.

(b) Applies to slope within the clear zone only. Other design features, such as guardrails or retaining walls, should be considered in particularly sensitive areas in lieu of reconstructing the inslope in accordance with part 8820.4060.

(c) Guardrail is required to be installed at all bridges where the design speed exceeds 40 mph, and either the existing ADT exceeds 400 or the bridge width is less than the sum of the lane and shoulder widths.

Mailbox supports must be in accordance with chapter 8818.

(d) Inventory rating of HS 15 is required. A bridge narrower than these widths may remain in place if the bridge is not deficient structurally or hydraulically.

HS 20 loading with AASHTO Standard Specifications or HL-93 loading with load and resistance factor design (LRFD) is required for new bridges. HS 18 loading is required for all rehabilitated bridges. The curb-to-curb minimum width for new or reconstructed bridges is the sum of the lane and shoulder widths plus four feet.

Ditch depths and widths must be kept to the minimum required to function hydraulically and to provide for adequate snow storage when a standard ditch would negatively impact the surroundings.

The designer shall specify in the plan and special provisions that the clearing width is to be kept to the absolute minimum. In sensitive areas, the normal clearance allowed to a contractor for working room is zero unless otherwise required for special conditions.

Curb and gutter may be used in lieu of a ditch section under the paved option. The lane width, shoulder width, and clear zone must be maintained.

For designated national forest highways within national forests, and state park access roads within state parks, this subpart applies only where the projected ADT is less than 100, unless the route has been designated as a natural preservation route.

For roundabout design, the design criteria of the current edition of the Minnesota State Aid Roundabout Guide are recommended.

Subp. 2.Type II route.

New or reconstruction projects for type II natural preservation routes, designated national forest highways within national forests, and state park access roads within state parks must meet or exceed the minimum dimensions indicated in the following design chart.

Surface Type	Design Speed	Lane Width	Shoulder Width	Inslope	Clear Zone	Design Strength	Bridge to Remain
	(mph)	(feet)	(feet)	(rise: run)	(feet)	(tons)	(feet)
			(a)	(b)	(c)		(d)
Aggregate	30	11	2	1:3	9		22
Paved (e)	30	11	3	1:4	9	9	22
Paved	40	11	3	1:4	9	9	22

(a) The designer will provide a six-foot paved shoulder if the route is a popular bicycle route. If the route has scenic vistas that will require parking vehicles along the shoulder, widening the shoulder at these locations is acceptable.

(b) Applies to slope within clear zone only. Other design features, such as guardrail or retaining walls, should be considered in particularly sensitive areas in lieu of reconstructing the inslope in accordance with part 8820.4060. Approach sideslopes must be 1:4 or flatter within the clear zone when the ADT exceeds 400.

Mailbox supports must be in accordance with chapter 8818.

(d) This standard may be applied only when the project is located in a subdivided area.

(e) Inventory rating of HS 15 is required. A bridge narrower than these widths may remain in place if the bridge does not qualify for federal-aid bridge funds.

Ditch depths and widths must be kept to the minimum required to function hydraulically, to be traversable if within the clear zone, and to provide for adequate snow storage when a standard ditch would negatively impact the surroundings.

For designated national forest highways within national forests, and state park access roads within state parks, this subpart may be applied only where the projected ADT is less than 300, unless the route has been designated as a natural preservation route.

For roundabout design, the design criteria of the current edition of the Minnesota State Aid Roundabout Guide are recommended.

Subp. 3.Type III route.

New or reconstruction projects for type III natural preservation routes, designated national forest highways within national forests, and state park access roads within state parks must meet or exceed the minimum dimensions indicated in the following design chart.

Surface Type	Design Speed	Lane Width	Shoulder Width	Inslope	Clear Zone	Design Strength	Bridge to Remain
	(mph)	(feet)	(feet)	(rise: run)	(feet)	(tons)	(feet)
			(a)	(b)	(c)		(d)
Aggregate	30	12	3	1:4	10		24
Paved (e)	30	12	4	1:4	10	9	24
Paved	40	12	4	1:4	15	9	24

(a) The designer will provide a six-foot paved shoulder if the route is a popular bicycle route. If the route has scenic vistas which will require parking vehicles along the shoulder, widening the shoulder at these locations is acceptable.

(b) Applies to slope within the clear zone only. Other design features, such as guardrail or retaining walls, should be considered in particularly sensitive areas in lieu of reconstructing the inslope in accordance with part 8820.4060. Approach sideslopes must be 1:4 or flatter within the clear zone when the ADT exceeds 400.

Mailbox supports must be in accordance with chapter 8818.

(d) Inventory rating of HS 15 is required. A bridge narrower than these widths may remain in place if the bridge does not qualify for federal-aid bridge funds.

(e) This standard may be applied only when the project is located in a subdivided area or an area in a detailed development process, and physical restraints are present that prevent reasonable application of another level of these standards.

HS 25 loading with AASHTO Standard Specifications or HL-93 loading with load and resistance factor design (LRFD) is required for new bridges. HS 18 loading is required for all rehabilitated bridges. The curb-to-curb minimum width for new or reconstructed bridges is the sum of the lane and shoulder widths, but may not be less than 32 feet.

For roundabout design, the design criteria of the current edition of the Minnesota State Aid Roundabout Guide are recommended.

Minn. R. Part 8820.9981

20 SR 1041; 23 SR 1455; 24 SR 1885; 29 SR 449; 32 SR 608; 36 SR 925

Statutory Authority: MS s 14.389; 162.02; 162.09