Rail Transportation Passby Noise and Impact Evaluation, An Historical Perspective

摘要

Before the publishing of the FTA Transit Noise and Vibration Impact Assessment Manual in 1996, methods of conducting environmental assessments of noise from transit systems used the maximum passby level with an inferred or measured ambient condition to evaluate transit noise impacts. This was APTA criteria developed in the 1970s. An alternate method, prescribed in the 1996 FTA manual, uses an SEL or L_(max) to characterize the train noise and determines noise impact based on the noise level increase in terms the Ldn. Over the last two decades, many transit agencies which originally used the earlier passby criteria have transitioned to the FTA-prescribed method as their basis of design. Wilson Ihrig recently conducted measurements on an existing rail system which used the APTA criteria during design of the initial system. The underlying passby analysis method used to develop the APTA criteria yields a different result from the current L_(max) method. With data measured on a variety of rail transit and commuter systems across the US, the current study takes a closer look at the different methods of assessing transit noise and compares their results. The implications for evaluating passby noise on existing systems will be presented and discussed.