| Source |
Lden |
Lnight |
Lday |
Levening |
LAeq,16hr |
| Major Roads Those which have more than three million vehicle passages a year (for mapping rounds other than Round 1) |
The day-evening-night level indicator for overall annoyance, based upon annual average A-weighted long-term sound over 24 hours. It includes a 5 dB(A) penalty for evening noise (19:00-23:00) and a 10 dB(A) penalty for night-time noise (23:00-07:00) |
The night level indicator for sleep disturbance, based upon the A-weighted, Leq (equivalent sound level) determined over all the 8-hour night periods (23:00-07:00) of a year |
The day level, the A-weighted, Leq (equivalent sound level), determined over all the 12-hour day periods (07:00-19:00) of a year |
The evening level, the A-weighted, Leq (equivalent sound level) determined over all the 4-hour evening periods (19:00-23:00) of a year |
The equivalent continuous sound level in dB(A) that, over the period 07:00-23:00 hours, contains the same sound energy as the actual fluctuating sound that occurred in that period |
