VMT is Vehicle Miles Traveled.
AADT is Annual Average Daily Traffic.
A road segment's VMT value is calculated by multiplying that road segment's AADT value by the length of that road segment in miles.
For reporting purposes, each route's VMT value is included on Georgia's Mileage/VMT reports. To calculate a route's VMT, accumulate the road segment VMT values for all of the road segments of that route.