Which delivery method combines design and construction responsibilities into a single contract?

The delivery method that combines design and construction responsibilities into a single contract is design-build. This approach streamlines the project delivery process by integrating the design and construction phases under one contract, which can facilitate better communication and collaboration between the design and construction teams.

In design-build, the project owner hires a single entity to manage both the design and construction, which can lead to faster project completion since any design changes can be addressed more quickly without the need for separate contracts or lengthy negotiation processes. This method can also reduce the risk for the project owner, as they have a single point of accountability for the project's success.

This contrasts with other methods such as design-bid-build, where the design and construction phases are handled by separate entities, often leading to increased time lost in transitioning between these phases. Similarly, construction management at risk also involves separate contracts and can add complexity to the project management process. Traditional contracting, much like design-bid-build, does not provide the integrated approach that design-build offers. Thus, design-build is particularly effective for projects where collaboration, efficiency, and speed are vital.