Cyclists who must swerve because of wind or to avoid debris may hit divots and lose control. It was hoped these depressions with curved bottoms would be bike friendly, and with their better quality control would provide good solution for narrow shoulders. Such is not the case. For lack of other standards, DOTs use the article for guidance. The increased spacing was of very little help.
Problem seems to lie in shape of depression.
Wheel drops into wide curved shape and is immediately forced up and out again, creating the severe jarring effect. In order to ease problem of crossing rumbles, Arizona is considering skip pattern, alternating lengths of milled in rumbles with 12 ft lengths of clear shoulder. Arizona also proposing to reduce strip widths below their present 12 inches, down to 8 or even 5 inches, to increase remaining rideable space. Both proposals will help, but will not reduce jarring action when bike hits divots on narrow shoulders. In the face of ongoing loss of cycleable roads, HPT Com would recommend a moratorium on SRS installation where remaining smooth surface would be less than say 5 ft wide, until a more bike-friendly rumble configuration is identified and tested.