one I found was from the 1950s, before the PANYNJ widened the approaches!
This one?
By the way, the approaches were not widened. The sidewalks were removed to allow the lanes to be widened on the existing structure.
Anyway, those raised walls exist in various sections but you will notice they're all where the approach roadway either crosses a street or has a house right next to it. The purpose is to prevent debris that is blown or thrown from vehicles from being able to fall on the streets below and cause damage or injury.
Meanwhile they're considerably older than 2000 - they're not visible in that image you found because it's taken from much closer to the main span, so they'd all be in the background where everything is too blurry to discern.
A perusal of
Historic Aerials indicates they were installed between 1963 and 1966.