Noise zone of strategic noise maps 4th deadline, for the A85 motorway, type A (exposed areas) in Lden

Noise zones are geometrical components of the strategic noise map. For Type A maps (CBSTYPE), each noise zone is generally bounded by 2 isophone curves (Lden 55-60, 60-65, 65-70, 70-75 and Ln 50-55, 55-60, 60-65, 65-70) or the lower limit isophone curve (Lden > 75, Ln > 70). For type C maps (CBSTYPE), each noise zone is bounded by the lower limit isophone curve (Lden > 68 or 73, Ln > 62 or 65).噪声区是战略噪声地图的几何组成部分。对于A型地图（CBSTYPE），每个噪声区通常由两条等声级曲线（Lden 55-60、60-65、65-70、70-75以及Ln 50-55、55-60、60-65、65-70）界定，或以一条下限等声级曲线（Lden > 75、Ln > 70）作为边界。对于C型地图（CBSTYPE），每个噪声区以一条下限等声级曲线（Lden > 68或73、Ln > 62或65）作为边界。