Just driving around in a circle and attacking the opponent might get boring. Why not throw in environmental hazards? Environmental hazards throw in some randomness to the battles and give the players more to watch out for.
These hazards will do damage, slow down the chariot, or even visual obstruction. Some examples of hazards include:
Wooden spike strip
Puddles of water
Wooden Spikes --> Laid out at random by AI to trip up and make the track harder to traverse.
Shooting Flames --> Tubes pointing out from the inside of the arena will cut on and off randomly to burn players throughout the race.
Smoke Screen --> A cloud of smoke will randomly overtake a small portion of the arena to temporarily blind the racers, caused by stadium go-ers burning straw in the crowd.