Table 6.2. GDOT Design Standards for Collector Roadways

Item No.

Item

Rural

Urban(1)

1

Design Speed(2)

40 mph

50 mph

60 mph

30 mph

40 mph

45 mph

2

Level of Service(3)

C

C

C

C

C

C

3

Number of Travel Lanes

2 min-4 typ.

2 min-4 typ.

2 min-4 typ.

2

2 min-4 typ.

2 min-4 typ.

4

Width of Travel Lanes(4)

12-ft.

12-ft.

12-ft.

12-ft.

12-ft.

12-ft.

5

Overall Width of Shoulders

    Outside

10-ft.

10-ft.

10-ft.

n/a

n/a

n/a

    Median(5)

6-ft.

6-ft.

6-ft.

6-ft.

6-ft.

6-ft.

6

Width of Paved Shoulders

    Outside

6.5-ft.

6.5-ft.

6.5-ft.

n/a

n/a

n/a

    Median(5)

2-ft.

2-ft.

2-ft.

2-ft.

2-ft.

2-ft.

7

Width of Median

    Depressed

n/a

n/a

32-ft.–44-ft.

n/a

n/a

n/a

    Raised

20-ft.–24-ft.

20-ft.–24-ft.

20-ft.–24-ft.

20-ft.–24-ft.

Turn Lane (6)
plus 8-12ft.

Turn Lane (6)
plus 8-12ft.

    Flush

14-ft.

14-ft.

14-ft.

14-ft.

14-ft.

14-ft.

8

Sidewalk

    Width of Sidewalk

n/a

n/a

n/a

5-ft.

5-ft.

5-ft.

    Sidewalk Offset from Curb

n/a

n/a

n/a

6-ft.

6-ft.

6-ft.

9

Width of Bike Lanes(5)

n/a

n/a

n/a

4-ft.

4-ft.

4-ft.

10

Fore Slope – Ratio

2:1 max.

4:1

4:1

2:1 max.

2:1 max.

2:1 max.

11

Back Slope – Ratio

2:1 max.

2:1 max.

2:1 max.

2:1 max.

2:1 max.

2:1 max.

12

Pavement Cross Slope

0.02-ft./ft.

0.02-ft./ft.

0.02-ft./ft.

0.02-ft./ft.

0.02-ft./ft.

0.02-ft./ft.

13

Stopping Sight Distance(7)

305-ft.

425-ft.

570-ft.

200-ft.

305-ft.

360-ft.

14

Maximum Superelevation

0.06-ft./ft.

0.06-ft./ft.

0.06-ft./ft.

0.04-ft./ft.

0.04-ft./ft.

0.04-ft./ft.

15

Minimum Radius

    Without Superelevation (+ .02)(8)

3,770-ft.

5,700-ft.

8,060-ft.

1,880-ft.

3,220-ft.

4,040-ft.

    Without Superelevation (- .02)(8)

5,230-ft.

7,870-ft.

11,100-ft.

2,830-ft.

4,770-ft.

5,930-ft.

16

Minimum Radius (w/ Superelev.)(8)

485-ft

833-ft.

1,330-ft.

250-ft.

533-ft.

711-ft.

17

Maximum Grade (%)(9)

    Level

7%

6%

5%

9%

9%

8%

    Rolling

8%

7%

6%

11%

10%

9%

    Mountainous

10%

9%

8%

12%

12%

11%

18

Minimum Vertical Clearance(10)

14.5-ft.

14.5-ft.

14.5-ft.

14.5-ft.

14.5-ft.

14.5-ft.

19

Minimum Horizontal Clearance

    From Edge of Travel Lane(11)

26-ft.

26-ft.

26-ft.

n/a

n/a

n/a

    Outside (From Back of Curb) (ft.)

n/a

n/a

n/a

6 typ. - 15

6 typ. - 15

6 typ. - 15

    Median (From Back of Curb) (ft.)

n/a

n/a

n/a

4 typ. - 15

4 typ. - 15

4 typ. - 15

20

Minimum Width of Right of Way(12)

As needed

As needed

As needed

As needed

As needed

As needed

Notes:

(1) Applies to curbed sections only unless stated otherwise. Use rural standards for uncurbed sections.

(2) See current AASHTO Green Book guidelines. Also see notes 6, 7, and 8 below for design speeds not shown

(3) LOS D is permissible in heavily developed areas.

(4) May be reduced to 11-ft. for urban type A.

(5) Applies to uncurbed sections.

(6) GDOT prefers the use of 24-ft. raised median if there are minimal impacts associated with a wider median.

(7) Values shown are for the given design speed. For other design speeds, refer to current AASHTO Green Book, Chapter 3.

(8) Values shown are for the given design speed. For other design speeds, see current AASHTO Green Book, Chapter 3.

(9) Values shown are for the given design speed.  For other design speeds, see Chapter 4 of this Manual.

(10) Minimum values are for vehicular clearances. Please refer to the current GDOT Bridge and Structures Policy Manual for further information, clearances at other facilities and limitations.

(11) Minimum horizontal clearance equals to clear zone plus 4-ft. typical ditch.

(12) Please refer to Section 6.10.  of this Manual for determination of width of required right of way