LAC 70:I.1321 – Minimum Design Guidelines for Urban and Suburban Collector Roads and Streets

Item No.	Item	Urban	Suburban¹
		UC-1	UC-2	SC-1	SC-2	SC-3
1	Average Daily Traffic	N/A	N/A	N/A	N/A	N/A
2	Design Speed (mph)	30–40	45	40	45	50
3	Number of Lanes (minimum)	2–4	2–4	2–4	2–4	2–4
4	Width of Travel Lanes (ft)	11–12	12²	11	11	11–12²
5	Width of Shoulders (ft)
	(a) Inside on multilane facilities	N/A	N/A	N/A	N/A	4³
	(b) Outside	8^{2, 4}	8²,⁴	4–5⁴	4–5⁴	6, 8⁵
6	Shoulder Type	Paved	Paved	Paved	Paved	Paved
7	Width of Parking Lanes (where used) (ft)	7–10⁶	11	7–10⁶	11	N/A
8	Width of Median on multilane facilities (ft)
	(a) Depressed	N/A	N/A	N/A	N/A	30
	(b) Raised	4 (min)–30 (des)	4 (min) –30 (des)	4 (min)–30 (des)	4 (min)–30 (des)	26
	(c) Two way left turn lane	11–14 typ.⁷	11–14 typ.⁷	11–14 typ.⁷	11–14 typ.⁷	N/A
9	Width of Sidewalk (minimum) (where used) (ft)⁸
	(a) When offset from curb	4	4	4	4	4
	(b) When adjacent to curb	6	6	6	6	N/A
10	Fore Slope (vertical – horizontal)	1:3–1:4⁹	1:3–1:4⁹	1:4	1:4	1:4
11	Back Slope (vertical – horizontal)	1:3¹⁰	1:3	1:3	1:3	1:3
12	Pavement Cross Slope (%)	2.5	2.5	2.5	2.5	2.5
13	Minimum Stopping Sight Distance (ft)	200 (30mph) 305 (40mph)	360	305	360	425
14	Maximum Superelevation (%)	4	4	4	4	6
15	Minimum Radius (ft)^{11, 12}
	(a) With normal crown (-2.5% cross slope)	325(30mph) 700(40mph)	1,000	700	1,000	16,700
	(b) With 2.5% superelevation	250(30mph) 550(40mph)	750	550	750	4,400
	(c) With full superelevation	235(30mph) 500(40mph)	700	500	700	900
16	Maximum Grade (%)	9	8	7	6	6
17	Minimum Vertical Clearance (ft)¹³	15	15	15	15	15
18	Minimum Clear Zone(ft)
	(a) From edge of through travel lane	10	10	10	10	26 – 28¹⁴
	(b) Outside from back of curb (when curb is used)	1 (min)―6 (des)	6 (min)―8 (des)	1 (min)―6 (des)	6 (min)―8 (des)	17 – 19¹⁵
	(c) Median from back of curb (when curb is used)	1 (min)―6 (des)	1 (min)―8 des)	1 (min) – 6 (des)	1 (min)―8(des)	13
19	Bridge Design Live Load¹⁶	AASHTO	AASHTO	AASHTO	AASHTO	AASHTO
20	Minimum Width of Bridges (face to face of bridge rail at gutter line)
	(a) Curbed facilities (without sidewalks)	Traveled¹⁷way plus 8'	Traveled¹⁷way plus 8'	Traveled¹⁷ way plus 8'	Traveled¹⁷ way plus 8'	Roadway width
	(b) Shoulder facilities	Roadway width	Roadway width	Roadway width	Roadway width	Roadway width
21	Guardrail Required at Bridge Ends	¹⁷	¹⁷	¹⁷	¹⁷	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 30:811 (April 2004), repromulgated LR 30:2337 (October 2004), amended LR 35:2846 (December 2009).