Hey all.  Wanted to do something new and different for my home group.  Thought a good old horse chase on the way to the next town might spice things up.  Let me know what you think.

Wagon and Horse Chase Rules for 5e
-These rules govern an encounter between riders on horses trying to overtake a wagon driven by a team.
-Horses and their driver or rider roll Initiative together and share a place in the Initiative order.  However, they take their turns separately. The horse will go first and the driver or rider takes their turn second.  Characters who are riding in a vehicle roll their Initiative separately from the horses and driver handling the vehicle in which they are riding.
-A wagon (four wheeled) is led by at least two draft horses, referred to below as a team, and a driver who can be either a PC or an NPC.  A carriage (two wheeled) is led by one or two draft or riding horses and a driver who can be either a PC or an NPC. A single horse has either a single rider or two riders.  The rider in the front is a driver.
-The wagon has an AC of 15.  It is made of wood. It is vulnerable to fire, lightning and radiant damage.  It is invulnerable to cold, necrotic, poison and psychic damage. The wagon has 90HP divided into three groups.  The box has 20HP. The bed has 35HP. The wheels have 35HP. The wagon reduces the team to half speed if either, the wagon’s total HP is reduced to 45, the box’s HP is reduced to 10 or either the bed or wheels’ HP is reduced to 15.
-On each of the team or horses’ turns, a DC must be passed to determine if the team or horse loses speed.  The DC is set at 2 for a team or horse that is fresh, fed and rested. The DC is 4 if they have been working for four hours.  The DC is 7 if the team has been working for seven hours.
-If the team or horse passes the DC then they maintain their full speed and on their next turn they must pass a DC that equals the current DC +1.  (Example, if the team passes a DC of 6, on their next turn they must pass a DC of 7.) If the team fails the DC, they lose speed equal to the DC number that they just failed and on the next turn they must pass a DC that equals the current DC +2. (Example, if a horse fails a DC of 5, it loses 5 speed and must pass a DC of 7 on its next turn.)  If the team or horse loses total speed that drops them below 30 feet per round, during the encounter, then it must come to a stop until the encounter is over and it has rested for a full two hours, regardless of the amount of work done previously during the day.
-If the team or horse fails a DC, the driver may perform an Animal Handling (Wisdom) check as a Bonus Action on their turn immediately following the horses’ turn.  If he or she passes a DC check of the current DC +3 then there is no loss of speed to the team or horse and their DC progresses normally. (Example, the horse failed on its DC of 11.  The driver then uses his or her Bonus Action to do an Animal Handling check and passes a DC of 14. The horses lose no speed and their next DC increases by only 1.) The driver may do this only three times per encounter.
-Drivers, as an Action on any of their turns, may also make a straight Perception (Wisdom) check at disadvantage.  If they pass a DC of 9 then there is no DC increase on the horses’ next turn and the horses regain up to 5 feet of their speed.  If the roll passes a DC of 14, the driver of a wagon team may also change direction on the same turn. If e or she fails the check, the team loses 1HP per horse bludgeoning damage and the wagon wheels take 2HP bludgeoning damage.
-If the team or horse is reduced to half HP, rounded down, during the encounter, then it must come to a stop until the encounter is over and it has rested for a full two hours, regardless of the amount of work done previously during the day.

Pick it apart and tell me what you like and what you might do differently.