This project developed a low-cost sensor system for autonomously monitoring and wirelessly reporting highway traffic noise data. The device reports noise measurements periodically (e.g., hourly or daily, as desired) to a receiver located up to 1.2 miles away. The technology incorporates embedded processing software that was developed to provide capability to measure sound in averaging modes, apply frequency weightings, and compute octave band analyses consistent with ANSI standards for Type 1 ratings. The sensor enclosures are readily mounted to a simple post or tripod and wireless transmission ranges of more than 1 mile were demonstrated through controlled testing. In conjunction with Ohio DOT funding, a total of 20 Smart Sensors for Autonomous Noise Monitoring (SSAM) were developed and tested. Field testing was successfully completed that also included demonstration of 16 SSAM units operating simultaneously and transmitting noise data wirelessly. The field work included noise barrier testing for the Ohio DOT and wayside measurements (statistical pass-by) in collaboration with the California DOT.  The developed prototype hardware was capable of performing low-cost noise monitoring at several locations simultaneously with wireless data transfer to a remote base station.  The SSAM prototypes are now available for demonstration or use in noise studies. The sensors are expected to cost less than $100 each (in large quantities), making them cost-effective to monitor many locations simultaneously (Figure 1).

Figure 1                                                                                                                                                                                                                                                                                          General concept of operation of a network of smart sensors for autonomous noise monitoring.

The contractor's final report is available.