Chapter 6 - Cross Section Elements

6.2. Typical Section Geometrics

6.2.2. Shoulders

All interstate ramp shoulders should be a full-depth, full-width paved shoulder. The standard shoulder cross-slope for total shoulder width and paved shoulder width adopted by the GDOT applies to all roadway classifications. As noted in the opening paragraphs of this Section, this can vary depending on project specifics. For instance, on some projects the paved shoulder cross-slope matches the roadway cross-slope.

 

On four-lane divided highways, the cross-slope on the median shoulder in tangent section is controlled by the cross-over crown restrictions described in Section 6.4. of this Manual. Similarly, the outside shoulder cross-slopes (the convex side of the curve) on superelevated roadways will be controlled by the cross-over crown restrictions. As a result, the slope will depend on the superelevation rate.

 

On superelevated roadways, the inside shoulder will maintain its normal crown slope for superelevation rates equal to or less than the normal shoulder slope. For superelevation rates greater than the normal shoulder rate, the inside shoulder slope is the same as the superelevation rate of the roadway. For additional discussion of the superelevation, refer to Chapter 4. Elements of Design, Section 4.5.

Rumble strips shall be used as follows:

• rumble strips are to be the milled-in type

• dimensions - 16 inches width, 7 inches length, ½ inch depth, 5 inches space between

• skip pattern - 28-ft. of rumble strips, 12-ft. clear space

Table 6.6. describes appropriate placement of rumble strips.

Table 6.6. Rumble Strip Placement
Roadway Type	Rumble Strip Placement
Interstate / Freeway*	Continuous
Multi-Lane Rural Section (design speed >50 mph)	Skip pattern
Two-Lane Rural Section (>400 ADT & >50 mph)
2-ft. Paved Shoulder	No rumble strip
>4-ft. Paved Shoulder	Skip pattern
*Where bicycles are NOT allowed

Refer to GDOT Construction Standards and Details, Construction Detail S-8 for drawings of 4-ft. and 6.5-ft. shoulders, each showing the placement of the rumble strips. The 6.5-ft. shoulder shall accommodate bicyclists based on AASHTO Guidelines and shall be the one shoulder consistently used on multi-lane widening and/or reconstruction projects with rural shoulders.

Under special circumstances, GDOT Construction Standards and Details, Construction Details T-19, T-23 and T-24 provide other applications for various rumble strip/rumble patch devices