Results: We found substantialvariations in traffic and noise with in and between cities.Totalnumberof
vehicle countsexpla in edasubstantialamountofvariationinmeasuredambientnoiseinAtlanta(78%),
Los Angeles(58%),andNewYorkCity(62%).Modelednoiselevelsweremoderatelycorrelatedwith
measured noiselevelswhenobservedtraffic countswereusedasmodelinput.Weakercorrelationswere
found whenMPOtraffic datawasusedasmodelinput.