SYMPOSIA PAPER Published: 01 January 2003

Evaluation of Pavement Smoothness and Pay Factor Determination for the Alabama Department of Transportation


In 1989 the Alabama Department of Transportation (ALDOT) added a policy to their smoothness specification that enables payments made to paving contractors to be based on the level of smoothness. The contractor can receive a 5% bonus for above average or a 5% penalty for below average smoothness readings. The measurement of smoothness has been based on the manual extraction of data from profilograph traces based on a 0.2 blanking band and resolution of 0.05. ALDOT has determined that more than three-quarters of all the 0.1 mile segments tested since the implementation of the specification have fallen in the 5% bonus range without an improvement in pavement ride quality. This observation resulted in the decision to conduct a study to determine; 1) if the ProScan™ hardware and software could be used to provide a reliable method of reducing profilograph traces, and 2) to investigate the feasibility and consequences of different smoothness pay factors. The results of the study support the ProScan™ system as a quick, accurate, and replicable method of reducing the profilographs. In addition, it was concluded that ALDOT should change the blanking band to a width of 0.0 and should adopt a combined step and continuous function method of determining incentive pay factors. With these pay factors in place ALDOT would have paid only 96.8% of the bid price for paving projects that brought 102% pay under the old step-wise function.

Author Information

Bowman, B
Auburn University, Auburn, AL
Ellen, BP
Stroup Gardiner, M
Auburn University, Auburn, AL
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Developed by Committee: D04
Pages: 3–26
DOI: 10.1520/STP10647S
ISBN-EB: 978-0-8031-5481-0
ISBN-13: 978-0-8031-3460-7