Scientists at Heriot-Watt University say traffic vibrations on bridges like the Queensferry Crossing could power sensors that monitor its safety FOR more than 100 years engineers have been trying to solve the problem of movement on rail and road bridges. Traffic and wind regularly cause low frequency vibrations to ripple through bridge building materials such as steel and concrete. Now, a team of Scots engineers are hoping the oscillations caused by heavy traffic at peak times could actually be used to improve the safety of structures including the Forth Road Bridge and the Queensferry Crossing. The energy created during vibrations would normally travel away from its source before dissipating.