La. Admin. Code tit. 70 § I-1309

Current through Register Vol. 50, No. 9, September 20, 2024
Section I-1309 - Minimum Design Guidelines for Local Roads and Streets

Item No.

Item

Rural

Urban

RL-1

RL-2

RL-3

UL-1

UL-2

1

Design Speed (mph)1

30

40

50

20

30

2

Average Daily Traffic

0-250

250-400

Over 400

N/A

N/A

3

Typical Number of Lanes

2

2

2

2

2

4

Minimum Width of Travel Lanes (ft)

9

9

11-122

10-113

10-113

5

Minimum Width of Shoulders (ft) 4

2

2

5-85

When used6

When used6

6

Shoulder Type

Aggregate

Aggregate

Aggregate

Paved

Paved

7

Minimum Width of Parking Lanes (where used) (ft)

N/A

N/A

N/A

7-Residential

8-Industrial

7-Residential

8-Industrial

8

Minimum Width of Sidewalk (where used) (ft)

(a) When offset from curb

N/A

N/A

N/A

4

4

(b) When adjacent to curb

N/A

N/A

N/A

6

6

9

Fore Slope (vertical-horizontal)

1:37

1:3 7

1:4

1:3

1:3

10

Back Slope (vertical-horizontal)

1:2

1:2

1:3

1:2

1:2

11

Pavement Cross Slope (%)

2.5

2.5

2.5

2.5

2.5

12

Minimum Stopping Sight Distance (ft)

200

305

425

115

200

13

Maximum Superelevation (%)

108

108

108

4

4

14

Minimum Radius (ft) 9, 10

(a) With normal crown (-2.5% cross slope)

7,585

11,625

16,700

100

325

(b) With 2.5% superelevation

1,930

3,250

5,000

85

250

(c) With full superelevation

250

450

700

80

235

15

Maximum Grade (%)11

7

7

6

10

9

16

Minimum Vertical Clearance (ft)

15

15

15

15

15

17

Minimum Clear Zone(ft)

(a) From edge of through travel lane

107

107

Varies12

7-Shoulder facilities

10-Shoulder facilities

(b) From back of curb (when curb is used)

N/A

N/A

N/A

1 (min)-6 (des)

1 (min)-6 (des)

18

Bridge Design Live Load13

AASHTO

AASHTO

AASHTO

AASHTO

AASHTO

19

Minimum Width of Bridges (face to face of bridge rail at gutter line)

Traveled

way plus 4'

Traveled

way plus 4'

Traveled 14

way plus 6'

Traveled 15, 16

way plus 8'

Traveled 15, 16,

way plus 8'

20

Bridge End Treatment

Yes

Yes

Yes

16

16

La. Admin. Code tit. 70, § I-1309

Promulgated by the Department of Transportation and Development, Office of Highways/Engineering, LR 30:808 (April 2004), repromulgated LR 30:2334 (October 2004), amended LR 35:2843 (December 2009).
AUTHORITY NOTE: Promulgated in accordance with R.S. 48:35(C).