The Kansas Department of Transportation (DOT) uses the 1993 DARWin version of the 1986 AASHTO Guide to design flexible pavements and rehabilitation strategies of flexible pavements. One of the inputs needed for the flexible pavement design procedure is the structural layer coefficient for each pavement layer. The Kansas DOT procedure to assign structural layer coefficients was developed years ago and based on an analysis of flexible pavement performance data and layer properties. It has been recently suggested that the Kansas DOT increase the structural layer coefficients because of changes in material and construction specifications. Different procedures can be used to estimate the structural layer coefficients for flexible pavement design. As part of the study entitled Determination of the Appropriate Use of Pavement Surface History in the KDOT Life-Cycle Cost Analysis Process an evaluation of the procedure that Kansas DOT uses to assign structural layer coefficients to different pavement materials was completed. This report provides the results of that evaluation.

Design related project level pavement management - Economic evaluation of alternative pavement design strategies - Reliability / - Pavement design procedures for new construction or reconstruction : Design requirements - Highway pavement structural design - Low-volume road design / - Pavement design procedures for rehabilitation of existing pavements : Rehabilitation concepts - Guides for field data collection - Rehabilitation methods other than overlay - Rehabilitation methods with overlays / - Mechanistic-empirical design procedures.

The Kansas Department of Transportation (DOT) uses the 1993 DARWin version of the 1986 AASHTO Guide to design rigid and flexible pavements. One of the inputs needed for the flexible pavement design procedure is the modulus of the subgrade soils, which has an effect on the total pavement thickness. Different procedures can be used to estimate the effective roadbed resilient modulus for flexible pavement design and effective modulus of subgrade reaction for rigid pavement design. As part of the study entitled Determination of the Appropriate Use of Pavement Surface History in the KDOT Life-Cycle Cost Analysis Process, an evaluation of the procedure that Kansas DOT uses to estimate the effective subgrade resilient modulus was completed. This report provides the results of that evaluation.

The objectives of this project were to collect, review, and summarize current state highway department pavement procedures and develop recommendations for revisions to the AASHO Interim Guides for the design of both rigid and flexible pavements.