[Are speed cameras able to reduce traffic noise disturbances? An intervention study in Luebeck]

Disturbance by traffic noise can result in health problems in the long run. However, the subjective perception of noise plays an important role in their development.

The aim of this study was to determine if speed cameras are able to reduce subjective traffic noise disturbance of residents of high-traffic roads in Luebeck?

In August 2012 a speed camera has been installed in 2 high-traffic roads in Luebeck (IG). Residents living 1.5 km in front of the installed speed cameras and behind them received a postal questionnaire to evaluate their subjective noise perception before (t0), 8 weeks (t1) and 12 months (t2) after the installation of the speed camera. As controls (CG) we asked residents of another high-traffic road in Luebeck without speed cameras and residents of 2 roads with several consecutive speed cameras installed a few years ago. Furthermore, objective measures of the traffic noise level were conducted.

Response rates declined from 35.9% (t0) to 27.2% (t2). The proportion of women in the CG (61.4-63.7%) was significantly higher than in the IG (53.7-58.1%, p<0.05), and responders were significantly younger (46.5±20.5-50±22.0 vs. 59.1±17.0-60.5±16.9 years, p<0.05). A reduction of the perceived noise disturbance of 0.2 point, measured on a scale from 0 (no disturbance) to 10 (heavy disturbance), could be observed in both IG and CG. Directly asked, 15.2% of the IG and 19.3% of the CG reported a traffic noise reduction at t2. The objective measure shows a mean reduction of 0.6 dB at t1.

The change of noise level of 0.6 dB, which could only be experienced by direct comparison, is in line with the subjective noise perception. As sole method to reduce traffic noise (and for health promotion) a speed camera is insufficient.