Sandy James Images
Via NYC Parks Commissioner Mitchell Silver is this Fast Company article on the Secret Life of Parks. Diana Budd explores the work in Brooklyn Bridge Park that Michael Van Valkenburgh Associates (MVVA) has undertaken in making parks quieter, even when surrounded by traffic and other noise. “By sculpting the land, MVVA gives cities their very own mute button.” 
In the parks of three major cities heavily impacted by traffic noise- Brooklyn Bridge Park in New York, Maggie Daley Park in Chicago, and A Gathering Place for Tulsa,  MVVA  decided that having a conversation at normal tone was a measure.  “If you have to yell or get really close together to talk, it’s not park-like . . . You try to lower ambient noise level so people can start to hear the insects.”
Sandy James Images
 I visited Brooklyn Bridge Park with NYC Parks Commissioner Silver. This park is a lineal one, and comprises of 85 acres south of the Brooklyn Bridge. There are several piers that were built when this was an active industrial shipping zone. While that industry left in the 1980’s, an area plan for parks and surrounding condominiums began being constructed in 2008. There  piers  have all been creatively adapted for reuse, including one that has basketball courts and a roller rink. A not for profit entity, the Brooklyn Bridge Park (or BBP) has waterfront walkways, playgrounds, a greenway, a pop up full-sized pool, and aims to make this a world-class waterfront park for all users.
MVVA images
But back to the noise. Because of its location next to a freeway ambient noise was at 75 decibels which is equivalent to sitting in a very loud restaurant. By creating a “heat map” of sound intensity, the MVVA group used three-dimensional modelling to figure out what kind of berm landscaping could mitigate the noise, and bring that down to a more park friendly 60 decibels, the level needed for hearing normal talking.
A huge grassed sound berm was created between the expressway and the park that significantly lowered the sound and provided more seating areas. Using similar modelling, landscape has been remodelled to lower acoustical levels in the parks in Chicago and Tulsa as well. The use of modelling has come up with some dynamic solutions to mitigate noisy surrounding soundscapes by landscape shaping and let the sound of nature itself take precedence even in very urban locations.