The associated Exit's ID
The distance, in miles, from the POI to the end of the Exit's off ramp.
L or R
Left or Right
On the POI Details page below, you will see where the Exit Mapping information is used. In the dark green bar below "Exxon" it says "Left (W) 0.32 miles". The "Left" comes from
turn_direction_long; the "W" comes from
cardinal_direction_short; and "0.32" comes from