6 electric car charging stations have been installed at a service station on a busy freeway. It is estimated that 1,200 vehicles pass through every hour, and that around 3% will stop to recharge.

Each customer takes an average of 20 minutes to charge, pay and then free up the space for the next customer. If all six bays were taken, the customer would park his car behind an occupied bay, and wait until it was free (the customer would not change bays while waiting). If all 6 bays and the 6 waiting spaces behind each bay were taken, a new customer would charge his car at another service station.

Part 1 Calculate bollard usage, the average number of cars in the station (charging or waiting to be charged) and the average time a car spends in the station.

Part 2 We'd now like to reorganize the kiosk space to accommodate a single queue. Consequently, if all six bollards were taken, a new customer would wait in a queue until a bollard became available. However, the queue could only accommodate a maximum of 3 cars.

Recalculate terminal usage, average number of cars in the station (charging or waiting to charge) and average time a car spends in the station.