The Weighted Average Source Distance (WASD) is used to calculate the distance food travels before being consumed or purchased. The measurement system combines information on the distances from production to point of sale and the amount of food product transported.

The WASD of a food product should be taken into consideration when trying to conserve energy. The average WASD for locally grown produce to reach institutional markets is 56 miles. The average WASD for conventional produe to reach institutional markets is nearly 1,500 miles (almost 27 times further than locally grown food). Remember, the farther food has to travel before it is eaten, the more energy used.

To learn more, go to:
http://www.leopold.iastate.edu/pubs/staff/files/food_travel072103.pdf