LAC 70:I.1317 – Minimum Design Guidelines for Suburban Arterial Roads and Streets

Item No.	Item	Suburban¹
		SA-1	SA-2
1	Design Speed (mph)	50	55
2	Level of Service	C	C
3	Number of Lanes	2 (min)-4 (typ)	2 (min)-4 (typ)
4	Width of Travel Lanes(ft)	12	12
5	Width of Shoulders (minimum) (ft)²
	(a) Inside on multilane facilities	4	4
	(b) Outside	8	8
6	Shoulder Type	Paved	Paved
7	Parking Lane Width (ft)	N/A	N/A
8	Width of Median on Multilane Facilities (ft)
	(a) Depressed	30–42	42
	(b) Raised	30	30
	(c) Two way left turn lane	N/A	N/A
9	Width of Sidewalk (minimum) (where used) (ft)³
	(a) When offset from curb	4	4
	(b) When adjacent to curb	N/A	N/A
10	Fore slope (vertical – horizontal)	1:4 to 1:6	1:6
11	Back slope (vertical – horizontal)	1:3	1:4
12	Pavement Cross-slope (%)	2.5	2.5
13	Minimum Stopping Sight Distance (ft)	425	495
14	Maximum Superelevation (%)	4	6
15	Minimum Radius (ft)^{4, 5}
	(a) With normal crown (-2.5% cross-slope)	16,700	19,700
	(b) With 2.5% superelevation	3,500	5,250
	(c) With full superelevation	1,000	1,100
16	Maximum Grade (%)	4⁶	4
17	Minimum Vertical Clearance (ft)⁷	16	16
18	Minimum Clear Zone(ft)
	(a) From edge of through travel lane	20 – 28⁸	24
	(b) Outside from back of curb (when curb is used)	10 (1:6) 18 (1:4)	14
	(c) Median from back of curb (when curb is used)	12	18
19	Bridge Design Live Load⁹	AASHTO	AASHTO
20	Width of Bridges (minimum) (face to face of bridge rail at gutter line)¹⁰
	(a) Curbed facilities (without sidewalks)	Roadway width	Roadway width
	(b) Shoulder facilities	Roadway width	Roadway width
21	Guardrail Required at Bridge Ends	Yes	Yes

Authority Note

AUTHORITY NOTE: Promulgated in accordance with R.S. 48:35(C).

Historical Note

HISTORICAL NOTE: Promulgated by the Department of Transportation and Development, Office of Highways/ Engineering, LR 30:810 (April 2004), repromulgated LR 30:2336 (October 2004), amended LR 35:2845 (December 2009).