Report Number



Currently, Indiana Department of Transportation (INDOT) is using the California Profilograph as the standard measuring device in its smoothness specifications. The output derived from the profilograph is called Profile Index (PI). PI represents the total accumulated deviations of the profilograph output traces beyond a tolerance zone (blanking band). At present, INDOT is using 0.2-inch blanking band to evaluate the profile traces, which has raised some concerns because some small unpleasant surface irregularities are covered by the blanking band. The major objective of this study was to develop a rational method for interpreting profilograph traces using 0.0-inch blanking band (zero tolerance) method and to establish corresponding pavement smoothness specifications. The secondary objective was to develop/adopt an automated system for the pavement profile analysis from printed profilograph traces. The study was divided into two parts. In the first part (synthesis study), a literature review was conducted to obtain information of smoothness specifications, smoothness measuring devices, and indices. Profilograph traces from several completed paving projects were analyzed using 0.2-inch and 0.0-inch blanking bands to develop manual reduction procedure for the 0.0-inch blanking band Profile Index. In the second part of the project, new PI0.0 construction smoothness specifications were developed by converting current PI0.2 smoothness specifications to the new PI0.0 specifications using developed conversion models. The converted PI0.0 specifications were then compared with the current Kansas DOT (KDOT) and other PI0.0 specifications. A partial verification of the converted PI0.0 specification was done by calculating pay factors for several recently completed paving projects measured using California profilograph. Measurement results were reduced manually and automatically by the Proscan system, which includes scanner and analysis program to reduce printed traces. It has been developed by Kansas State University and currently KDOT is using it in their construction QA procedures. The Proscan system showed excellent repeatability, and it saved considerable amount of time compared to the manual trace reduction. It is therefore recommended that INDOT uses Proscan system in their constitution QA operations. The converted PI0.0 specifications were also modified to comply with the Proscan reduction results.


Smoothness specification, zero blanking band, California Profilograph, Proscan, 0.2 in. blanking band, SPR-2711

SPR Number


Project Number


File Number


Performing Organization

Joint Transportation Research Program

Publisher Place

West Lafayette, IN

Date of this Version