Design-build contracts with performance-based specifications are believed to raise productivity and the innovation rate. However, performance-based requirements used in specifications for highway and bridge contracts may suffer from being too detailed or too difficult to verify. A Swedish research project has been devoted to this issue. The aims were (i) to develop a definition of performance-based requirements and (ii) to evaluate performance-based requirements used in Swedish design-build contracts. The project consisted of three parts: (i) literature survey, (ii) investigation of current documents produced and used by the Swedish Transport Administration for design-build contracts, and (iii) case studies of six design-build contracts with performance-based requirements, including an analysis of specification documents and interviews with both client and contractor project managers. Current performance-based specifications show different degrees of detail. Measurable requirements are more frequently used on roads, and in particular on road surfaces, than on bridges. Further development is needed to promote technical innovations. Less detailed specifications and a shift to design-build-operate contracts with prolonged maintenance responsibility would also encourage the choice of more durable and long-lasting (=sustainable) solutions. The emphasis on Life Cycle Cost (LCC) in the reformulated contract award criteria in the EU public procurement directive might be insufficient to strengthen the competitive power of concrete pavements as compared to asphalt pavements, unless specifications are supported by Life Cycle Analysis (LCA) and the choice of contract type is reconsidered.