| 摘要 |
<p>A system for determining the condition of a traffic controlling semaphore (12) has an audio sensor (16) mounted in the vicinity of an intersection (10, 11) so the sound level is monitored at all times. A computer (18) is placed into the semaphore controller (19), and the computer receives the audio signal, a time signal (22), and a signal representing the status of the semaphore. When a sound is detected above a certain minimum level, which is above the usual traffic noise, a record is generated by the computer, and recorded in permanent form, perhaps printed on paper (24). The record includes the date, time, and status of the semaphore.</p> |
