https://www.dot.state.mn.us/environment/noise/pdf/metro-noise-study.pdf https://www.dot.state.mn.us/environment/noise/pdf/metro-nois... page 6: Minnesota classe

https://www.dot.state.mn.us/environment/noise/pdf/metro-noise-study.pdf https://www.dot.state.mn.us/environment/noise/pdf/metro-nois... page 6: Minnesota classes some speed limit reductions as noise abatement. Washington refers to modifying speed limits with the goal of noise abatement: https://wsdot.wa.gov/sites/default/files/2021-10/ENV-ANE-NoisePolicy2020.pdf https://wsdot.wa.gov/sites/default/files/2021-10/ENV-ANE-Noi... page 20 Delaware includes modifying speed limits (classed as traffic management) for noise abatement: https://deldot.gov/Programs/highway_noise/index.shtml https://deldot.gov/Programs/highway_noise/index.shtml as a counterexample, https://wisconsindot.gov/dtsdManuals/traffic-ops/manuals-and-standards/teops/13-05.pdf https://wisconsindot.gov/dtsdManuals/traffic-ops/manuals-and... various pages: Wisconsin forbids using speed limit reductions as noise abatement.