Slow-Going Vehicles.
—Horse-drawn vehicles should travel on the outer side of the road if possible in order to allow faster going vehicles to pass them readily. Often a slow-going truck will take the middle of the roadway and stubbornly keep it even when asked courteously by horn to get over. In trying to pass by going partially off the paved way motors have slipped down due to the soft earth shoulders, with serious injuries to both persons and machines. Where traffic is heavy congestion results from slow-going vehicles not taking the outer side of the way, with its usual disastrous effects.