5.1.2 Target Design Values

Table 5-1

shows target design values for Local Roads in each context classification. These design values may be adjusted based on the anticipated operating speed and a performance-based practical design evaluation of the corridor as discussed in

Chapter 2

The target design values shown are for new construction of local roads that are off-system routes not functionally classified at a higher classification. Projects to improve existing local roads differ from new construction in that the performance of the existing local road can guide the selection of design values.

The following subsections provide additional discussion for each design element and factors that may influence these values.

The design value thresholds for design exceptions and design waivers are presented in Appendix A and B respectively.

Table 5-1: Target Design Values for Local Roads
Design Element			Rural	Rural Town	Suburban	Urban	Urban Core	Reference
Roadway		Design Speed ¹	40 to 50 MPH	25 to 30 MPH	40 MPH	25 to 30 MPH	20 to 25 MPH	See 5.1.3
		Lane Width	12-ft	11 to 12-ft	12-ft	11-ft	11-ft	See 5.1.6
		Shoulder Width (Uncurbed)	8-ft	4-ft	10-ft	8-ft	2-ft	See 5.1.7
		Offset to Face of Curb	N/A	1-ft	2-ft	2-ft	2-ft	See 4.10.12
		Curb Parking Lane Width²	N/A	9-ft	N/A	9-ft	9-ft	See 4.10.16
		Bike Lane Width	See 18.4
		Speed Change Lane Width	12-ft	11 to 12-ft	12-ft	11-ft	11-ft	See 4.10.2
		Median Width	See 4.10.15
		Horizontal Curve Radius (Minimum)	See 4.7
		Cross Slope on a Tangent	2%					See 4.10.4
		Cross Slope on a Tangent (Maximum)	3%					See 4.10.4
		Superelevation Rate	See Table 4-3 through Table 4-7					See 4.7.3
		Minimum Grade (PGL)	0.25% (lined ditch channels), 0.3% (curbed facilities), or 0.5% (unpaved ditches)					See 4.8.1
		Maximum Grade (Level)	6%	8%	8%	8%	8%	See 4.8.1
		Maximum Grade (Rolling)	8%	8%	8%	8%	8%	See 4.8.1
		Vertical Clearance	16.5-ft					See 4.8.6
		Design Loading Structural Capacity	HL-93					AASHTO LRFD Bridge Design Specifications
		Stopping Sight Distance (SSD)	See 4.11.1
		Design Vehicle	S-BUS-40					See 4.3.2
		Level of Service (LOS Design Year)	See 5.1.5					See 4.3.4.1
Roadside		Clear Zone (Curbed)	See 4.10.7
		Clear Zone (Uncurbed)	See 4.10.7
		Sidewalk Width	N/A	6 to 8-ft	6 to 8-ft	6 to 8-ft	6 to 8-ft	See 19.2.2
		Sidewalk Offset	N/A	Varies				See 19.3.2
		Border Width³	N/A	10-ft	10-ft	10-ft	10-ft	See 4.10.9
Notes		Denotes that this is a design exception condition if the specified values in Appendix A are not met.
		Denotes that this is a design waiver condition if the specified values in Appendix B are not met.
	1	The selected Design Speed should meet the anticipated operating speed of the facility during non-peak hours.
	2	If a bike lane is adjacent to a parking lane, the parking lane width should be increased to 12-ft to allow car doors to be open without bicyclist conflict. See Section 4.10 for additional guidance.
	3	A 2-ft border width may be used where available ROW is limited or too costly.

5.1 Design Considerations