setActionStepLength(string, double, bool) -> None

        Sets the action step length for this vehicle. If resetActionOffset == True (default), the 
        next action point is scheduled immediately. if If resetActionOffset == False, the interval 
        between the last and the next action point is updated to match the given value, or if the latter
        is smaller than the time since the last action point, the next action follows immediately.

def setActionStepLength(self, vehID, actionStepLength, resetActionOffset = True):
        """setActionStepLength(string, double, bool) -> None

        Sets the action step length for this vehicle. If resetActionOffset == True (default), the 
        next action point is scheduled immediately. if If resetActionOffset == False, the interval 
        between the last and the next action point is updated to match the given value, or if the latter
        is smaller than the time since the last action point, the next action follows immediately.
        """
        if actionStepLength < 0:
            raise exceptions.TraCIException("Invalid value for actionStepLength. Given value must be non-negative.")
        # Use negative value to indicate resetActionOffset == False
        if not resetActionOffset:
            actionStepLength*=-1
        self._connection._sendDoubleCmd(
            tc.CMD_SET_VEHICLE_VARIABLE, tc.VAR_ACTIONSTEPLENGTH, vehID, actionStepLength)