Jeff, as a native East Meadowite, you should remember LIRR crossings butting right up against Sunrise Highway through Merrick, Bellmore, Seaford and Massapequea Park and the monumental traffic jams accompanying passing trains.
I'm too young, but you might also remember when Hicksville was also at grade level- I think it was raised in 1962? 1965? And this was AFTER the adjacent mall was built!
Not a transit memory, but I sure miss those old wooden Parkway poles.