Louisiana Administrative Code
Title 70 - TRANSPORTATION AND DEVELOPMENT
Part I - Highway Construction
Chapter 13 - Design Guidelines for Freeways, Arterial, Collector, and Local Highways under the Jurisdiction of Political Subdivisions and Not in the State-Maintained System
Section 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

82, 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)

Traveled17 way plus 8'

Traveled17 way plus 8'

Traveled 17 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