The improvement of highway shoulders, from the standpoint of appearance and practical value, has been and is at present of considerable interest to all highway departments. A great deal of effort has been expended in the past to develop grass combinations which not only will prevent natural erosion of the surface materials but also impart a pleasing appearance to shoulders and slopes. Attempts to include factors of practical value, such as safe support of traffic loads, have greatly magnified the problem. Numerous types of paved shoulders have been introduced which are quite satisfactory with respect to load bearing but are expensive to construct and often do not equal in appearance the more attractive turf shoulders.

Stabilized turf shoulders have been adopted by several state and federal agencies in an attempt to combine aesthetic qualities with those of a practical nature. These shoulders are made principally of granular material but contain sufficient soil to support vegetation, and generally they are covered with a thin layer of topsoil to provide a seed bed. Limited data available indicate that these efforts have been rather successful.

The first study of stabilized turf shoulders in Kentucky was initiated during the 1954 construction season when the Division of Design designated an experimental section to be used for this purpose. This site was located on a 6 mile reconstruction project on U.S. 31-W and U.S. 68 from Bowling Green, to the intersection of the two routes at a point approximately 7 miles northward, Project No. I 16 (2) and 113 (5), see Fig. 1. The Division of Research was requested to observe and report on construction procedures and the effectiveness of turf shoulders constructed in this area.

The roadway located in this section consists of two traffic lanes in each direction, separated by a depressed median strip 2.0 feet wide. The median strip was constructed in the conventional manner and only the outside shoulders were stabilized. Three different means of stabilization were used, including hardstands at selected intervals with conventional earth shoulders in between.

Report Date


Report Number

No. 109

Digital Object Identifier