What is the difference between AADT and VMT?
One of the key variables in determining the VMT (Vehicle Miles Traveled) is the AADT (Annual Average Daily Traffic). The VMT is calculated by multiplying the AADT for a given road section times the length of the road section. This calculated value is the VMT for this road section. To accumulate this figure by route or to summarize for reporting purposes, this number is accumulated for every road section. For Example: You want to calculate the VMT for I-75. Since I-75 is a long route (355 miles) we know that it will have many road segments and AADT values to consider. For each road segment, the section length is multiplied by the applicable AADT for that segment and is accumulated. After this calculation has been performed on all of the road segments for I-75, the accumulated value is the VMT for I-75. In 2003, the Daily Vehicle Miles Traveled on I-75 was 29.2 million. This same calculation process is performed on all road segments for the State and is typically “rolled up” by functiona
