PPPs offer the opportunity for the private sector to apply its expertise to bring technical innovation to complex projects. One example is the application of a jet van tunnel ventilation system in the Largo Metrorail Extension project that saved an estimated $10 million in project costs over the vent shaft design that WMATA had constructed elsewhere in the Metrorail system, and is more cost-effective to operate and maintain than the agency's usual approach.
Denver's Southeast Corridor LRT project benefited from several technical and engineering innovations because contractors had the ability to propose technology equal to or better than that proposed in the project specifications. There were a total of approximately 100 so-called "Category B" changes, in which the contractor applied new technologies or found a better solution than originally proposed. Many of these changes cost the agency less money but provided a better product.
Portland's Tri-Met successfully applied design-build to fast-track the MAX Airport Extension project, in part because of the technical innovations it offered. A number of bridges constructed for the project had shafts being driven and piers built while the design detail for the bridges was being finished. When problems did arise, the agency found that design-builder Bechtel was quick to remedy the situation. The pier for a bridge over a freeway had an accident in which the concrete pour was contaminated and lost. In a traditional arrangement, in which responsibilities for design and construction are distinct, it may have taken six to eight weeks to resolve the issue. Under DB, the redesign by Bechtel took a matter of hours after it was realized the pier would require a new design.
South Florida RTA found that design-build offered the advantage of contractor provided input as design progressed for the South Florida Commuter Rail Upgrades project. The agency found that contractors have a lot of skilled employees who were able to provide the perspective of their experience constructing projects, which led to improved design.
From an operations standpoint, the private sector partner in a PPP should be given incentives to perform at or above the public agency's desired performance standards. NJ Transit discovered that its DBOM contract for the Hudson-Bergen LRT project did not adequately address the quality of service to the traveling public. While the consortium received a penalty or bonus for on-time performance, there were no incentives for station cleanliness or notification of customers of changes in service or other announcements, which became an issue. This experience highlights the need for detailed performance standards and proper incentives for performance.