Understanding weed seed transport by vehicles is important to help direct prevention activities (wash stations, road closures, public education, etc.) to reduce weed seed dispersal along trails and roads. Studies conducted by Montana State University measured the number and type of seeds picked up by vehicles and the distance seeds were transported. Different types of vehicles (trucks, ATVs, tracked vehicles), road surfaces (paved, unpaved, trails, off trails) and moisture conditions (wet and dry) were studied to determine how they affected seed dispersal. Results of the studies showed that vehicles can pick up large numbers of seeds, especially when driven off-trail, and under wet conditions. However, vehicles still collect seeds when staying on roads and trails.