Which just worsens the situation.
As Crowley points out; you don't know why the driver approaching you at speed is speeding, it could be a life-or-death situation. You would be solely responsible for any accidents caused due to believing it's your right to enforce the traffic laws. It's not, so don't. Mighty I just hope you're never in the situation where you are in a life-of-death situation and driver decides you shouldn't be speeding and brake-checks you. It's drivers like you who cause accidents most of the time, not those speeding.