NYS Route 119, AKA Tarrytown Rd, is a major east-west crossing,
from White Plains to Tarrytown on the Hudson. It was basically
supplanted by Interstate 287, AKA the Cross Westchester Expwy,
for cross county tripping, but still carries a fair share of
traffic, although it appeared quite sedate when this was shot.
Most of it's run includes grade level intersections, making this
underpassing of Route 100a an oddity. This is in the town of
Greenburgh, NY, about halfway between Hartsdale and Elmsford.
Route 100a to the right cuts a diagonal swath through Hartsdale, intersecting with sister NYS Routes 100b and 100 period, before giving up the ghost. If you ever find yourself here and want to get the Sprain Brook Pkwy to NYC, take 100a to 100b, turn right and the Pkwy is a couple of blocks up the hill.