Monitoring of civil structures is a growing application in nondestructive testing. Wireless systems supersede wired systems mainly by being easily deployable under various local structural conditions. The vast majority of today's existing structures are not equipped with monitoring systems by design. Wireless systems can still be installed as a retro fit. In the demonstration project described here, a 1350 m long motorway bridge over the Neckar River near Heilbronn, Baden-Württemberg, Germany was equipped with ambient and material temperature sensors as well as humidity sensors. The test setup is described in detail and interpretation of the data from initial measurements is provided. Furthermore, an assessment of the wireless monitoring system is presented, giving information about the packet drop rate, radio frequency calculations and wide-area network connectivity.