This map serves as a guide for truck and bus carriers as well as District residents to understand which routes are suitable for truck and bus travel. For the purposes of the map, a Truck is defined as a vehicle with a gross vehicle weight rating greater than 26,000 pounds with a carrying capacity of more than 1 and Â¼ ton. For the purposes of the map, a Bus is defined as a vehicle with a carrying capacity of greater than 15 passengers. This does not include WMATA or Circulator buses. A through route (highlighted in blue), signifies a roadway that may be used by trucks and buses that have neither an origin or destination within the city or on the route. A non-through route (all other roadways not highlighted in blue), signifies a roadway that that may be used by trucks or buses only for the purpose of making a delivery or pickup of passengers or freight. Trucks and buses should only use a non-through route at the beginning or end of a trip, when traveling between their origin/destination and a through route.