LAC 70:I.1305 – Minimum Design Guidelines for Freeways

Item No.	Item	Urban	Rural
		F-1	F-2	F-3¹
1	Design Speed (mph)	50	60	70
2	Level of Service	C³	C³	B 2
3	Number of Lanes (minimum)	4	4	4
4	Width of Travel Lanes (ft)	12	12	12
5	Width of Shoulders (ft)
	(a) Inside⁴	6	6	6
	(b) Outside⁵	10	10	10
6	Shoulder Type	Paved	Paved	Paved
7	Width of Median (minimum) (ft)
	(a) Depressed	50	68 (min)–100 (des)	72 (min)–100 (des)
	(b) Continuous barrier (4 lane)⁶	15	15	15
	Continuous barrier (6 lane)⁶	27	27	27
8	Fore Slope (vertical – horizontal)	1:4 to 1:6	1:6	1:6
9	Back Slope (vertical – horizontal)	1:4	1:4	1:4
10	Pavement Cross Slope (%)	2.5	2.5	2.5
11	Minimum Stopping Sight Distance (ft)	425	570	730
12	Maximum Superelevation (%)⁷	10	10	10
13	Minimum Radius (ft)⁸ (with 10% superelevation)	700	1,100	1,700
14	Maximum Grade (%)⁹	4	3	3
15	Minimum Vertical Clearance (ft)¹⁰	16	16	16
16	Width of Right-of-Way (ft)
	(a) Depressed median	As Needed	As Needed	Varies¹¹
	(b) Median barrier	As Needed	As Needed	As Needed
	(c) Minimum from edge of bridge structure¹²	15–20	15–20	15-20
17	Bridge Design Live Load¹³	AASHTO	AASHTO	AASHTO
18	Minimum Width of Bridges (face to face of bridge rail at gutter line) (ft)	Roadway Width	Roadway Width	Roadway Width
19	Minimum Clear Zone(from edge of through travel lane)(ft)
	(a) 1:4 Fore slope	30	N/A	N/A
	(b) 1:6 Fore slope	22	32	34

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 30:807 (April 2004), repromulgated LR 30:2333 (October 2004), amended LR 35:2841 (December 2009).