In conventional highway construction projects, there are three phases in which a State Department of Transportation (DOT) creates a design (in-house or with a contractor), opens a bidding process and selects a contractor—usually the one offering the lowest bid—to complete the construction. The process, known as design-bid-build (D-B-B), can lead to lengthy project delays because the process must be completed in sequential order and delays can occur from the lack of communication or sharing of expertise between the designer and contractor.
State DOTs have found that they can accelerate project delivery, lower project costs and improve project quality with an alternative project delivery method: design-build (D-B). In the D-B process, a State DOT identifies what it wants constructed, accepts proposals and selects a D-B team to assume the risk and responsibility for the design and construction phases. With D-B, DOTs generally have the option of selecting a D-B team based on a best-value basis; allowing DOTs to consider other factors beyond lowest price.
The D-B method accelerates project delivery, or shortens the project duration, in several ways. The contractor has flexibility in selecting the design, materials and construction methods based on the available equipment, work force and resources. The contractor also works closely with the designer, sharing his or her expertise, to reduce the risk of design errors and the need for redesigns, which can add to project costs and project delays. Allowing the contractor to tailor the project design and apply appropriate innovations provides flexibility for the contractor to manage and compensate for cost increases in one area through efficiencies in another. This does not include changes to environmental commitments, but control of the means and methods.
By awarding one contract in D-B, there is no bidding phase, or delay, between the design and construction phases. Services can even overlap. For instance, construction preparation can begin while the design is being created and finalized and the designer might need to be involved to assist with any redesigns if problems or concerns are encountered during the construction phase. Team work between the designer and contractor allows for greater collaboration and innovation and accelerated project delivery and often results in improved project quality.
Often through accelerated project delivery, the DOTs can reduce project durations by at least 1 to 2 years. Accelerated project delivery provides opportunities for significant cost savings and safety improvement. For example, shortened project durations reduce labor costs and safety risks associated with the maintenance of traffic (MOT) or work zones.
The DOTs can tailor D-B contracts for a wide variety of project needs. For example, the DOTs may choose to issue a design-build-operate-maintain (D-B-O-M) contract that includes additional operation and maintenance services. Design-build-operate-transfer and design-build-own-operate-transfer options may require the contractor to own or operate the facility for a period of time before transferring the responsibility back to the DOT. As State DOTs continue to use D-B contracts, greater flexibilities and benefits will be recognized.