In AR teams are only as fast as their slowest member. Teams that want to be competitive will almost always have towing as a big part of their game plan. On foot this can often be improvised - a piece of rope, extra strap, even a couple of leg warmers tied together can suffice to keep the team together and moving at the same pace. But for biking, it can be nice to have something more sophisticated that doesn't get in the way when it isn't in use but is ready to go at a moments notice. There are many types of tow systems out there - the following video shows the type i use when i race.