In August 1997, the Washington State Department of Transportation (WSDOT) adopted a strategy of closing a single direction of freeway over an entire weekend for constructing the overlay on a 5.5-mi (8.85-km) section of I-405. Work was performed over two weekends. Data were collected from field measurements, records, and surveys to assess construction quality, construction costs, and user impacts. Results were compared to historical data from WSDOT and from a National Cooperative Highway Research Program (NCHRP) synthesis study.
Overlay surface smoothness, density, and gradation quality were good, and no difference in consistency was found between night and day paving. Public response from motorists was decidedly positive, while business perceptions were mixed. Traffic simulations indicated that the total closure was preferable to single lane closures over multiple nights.
A decision checklist was developed for use in making the closure strategy decision.