Arup had been commissioned with the design of a new modular bridge system by Straßen.NRW, the road authority of Germany’s biggest state North Rhine-Westphalia. This article describes the background of this pilot project, the design concept, as well as the structural design and construction sequence of two new bridges, which can be erected within 8-10 weeks. The design is characterized by a high degree of prefabrication, modularity as well as the use of high performance concrete to ensure an excellent durability. The bridges are designed as integral frames – spanning about up to 30 m. The use of in-situ concrete had been kept to a minimum. The structures contain no bearings, no expansion joints and no separate parapets, which significantly reduces lifecycle costs. The use of high performance concrete made an additional waterproofing layer obsolete, which also saves construction time. The bridges are designed for replacement of deficient structures. To minimize demolition time, the foundations were designed so the existing foundations could remain in place.