DAYFREE is a construction method which enables deck slab replacement on expressways by closing lanes only at night, thereby reducing traffic congestion caused by lane closures.

In conventional deck slab replacement work, the lanes on the construction side are typically closed, with the traffic diverted onto the other side continuously until the construction is completed. However, in dense urban areas with high traffic volumes, continuous lane closures for day and night often become an extremely difficult construction challenge.

In response to this situation, the "DAYFREE" method with multiple technologies was developed to replace the deck slabs one lane at a time for sections to reduce the traffic congestion where full lane closures during peak traffic hours were not permitted.