This Trailster will accommodate 3 dogs in front pulling because I have redesigned the front end to add one more dog. I still am using the Sacco Cart spring loaded tow bar design but just incorporated one more into the mix!! I also added the ability to use two “Springers” one on each side to accommodate tow additional dog or puppies so they can ride with the pulling dogs but don’t have to pull. This is great for older dogs so they can exercise but not have to pull, smaller dogs which can not pull, and puppies which shouldn’t be pulling yet!! I have also added a misting system for warmer weather running. This will mist them as they run and constantly wet their fur and as this water evaporates off their fur it is cooling them as sweat cools a human!! In addition I have built a Canopy to shelter the driver in adverse weather conditions (some of my favorite times to run!!).