Should I model berms that are median barriers?
Yes. If a berm is a median barrier then it should definitely be modeled. Median barriers should be modeled as fixed-height barriers, unless the barrier is part of a noise barrier design, which is uncommon. A fixed-height barrier is a barrier that affects the sound level in both the “no barrier” and “with barrier” cases. Barrier attenuation is included in the “no barrier” sound level, which will equal the “with barrier” sound level. Fixed-height barriers are generally used for permanent structures, such as an existing wall; they are ineffective in barrier analyses. To implement: set all three perturbation values to zero. A Berm Top Width currently needs to be equal to zero. Do not use flat top berms.
