code: def setTau(self, vehID, tau):
          
          self._connection._sendDoubleCmd(
              tc.CMD_SET_VEHICLE_VARIABLE, tc.VAR_TAU, vehID, tau)
docs: setTau(string, double) -> None
  
          Sets the driver's tau-parameter (reaction time or anticipation time depending on the car-following model) in s for this vehicle.