For minimum acoustic performance, peak-hour is defined as M

Peak-hour is a term used to describe the time period when the traffic noise is highest, usually during morning and evening rush hours. Peak-hour noise level is measured by the equivalent continuous sound level (Leq), which is an energy-average of the noise level over a specified sample time. For minimum acoustic performance, LEED requires projects to implement acoustic treatment and other measures to minimize noise intrusion from exterior sources for high-noise sites (peak-hour Leq above 60 dBA during school hours).