Vehicle Miles Traveled (VMT)
Trips per person X miles per trip = VMT
The Vehicle Miles Traveled (VMT) per employee calculation combines the the number of people who share the trip (trips per person) with the length of the one-way commute trip (miles per trip). It reduces the person trips for employees who use high occupancy modes as shown at right.
For example: Joe commutes to work five days each week; he drives alone three days and carpools with a friend the other two days each week. His one-way trip is 10 miles.
3 drive-alone trips + 2 two-person carpool trips | X 10 miles per trip = VMT |
5 potential trips per person |
then,
3 drive-alone trips + (2 x 1/2 trips per person) | X 10 miles per trip = VMT |
5 potential trips per person |
then,
4 trips per person | X 10 miles per trip = VMT |
5 potential trips per person |
finally,
4 | X 10 = 8 Vehicle Miles Traveled |
5 |
Most employer programs will not affect the length of an employee's commute trip (the "miles/trip" portion of the VMT per employee equation) . But, employer programs can and do influence commute choice (the "trips/person" portion of the VMT per employee equation).
"Trips per person"
- A drive-alone trip (also includes one-person motorcycle and drive-on ferry trips) = 1 trip
- A two-person carpool = 1/2 trip per person
- A three-person carpool = 1/3 trip per person
- A four-person carpool = 1/4 trip per person
- A five-person carpool = 1/5 trip per person
- A six-person carpool = 1/6 trip per person
- Vanpools of less than seven but more than two occupants are counted as carpools (see above).
- Vanpools of seven or more and transit (bus, train or walk-on ferry) = 0 trip per person
- Trips not made because of teleworking and a compressed work week schedule and all non-motorized trips (bicycling, and walking) = 0 trip per person.