An approach to a pretimed signal with a 60- second cycle has nine vehicles in the queue at the beginning of the effective green. Four of the nine vehicles in the queue are left over from the previous cycle (at the end of the previous cycle's effective green). The saturation flow rate of the approach is 1500 veh/h, total delay for the cycle is 5.78 vehicle-minutes, and at the end of the effective green there are 2 vehicles left in the queue.

Determine the arrival rate assuming that it is unchanged over the duration of the observation period (from the beginning to the end of this 5.78-vehicle-minute delay cycle).