Problem 4

A new car registration and license issuing process for NSW Roads and Maritime Services (RMS) is being tested in Wollongong city. During the peak demand hours of 10:00 am to 1:00 pm, there is one customer arriving in average every 4 minutes, according to an exponential distribution.

Typically, 30% of the customers want to register their cars (only), 40% want to renew their licenses (only), and 30% want to do both (register their cars and renew their licences). The process is as follows: 

 Each customer gets into a line (with a maximum of 20 people allowed in that line).

 Once the customer reaches the counter, he/she informs a clerk at the counter what he/ she needs.

 The time of this discussion with the clerk can be approximated by a normal distribution with a mean time of 1.0 minute and a standard deviation of 0.5 minutes.

 The clerk at the counter gives each customer a number and shows him/her where to sit (there is plenty of room for customers to sit and wait).

 Those who want to do both (register their cars and renew their licences) get their licence renewed first.

 There are specific officers dedicated to particular tasks, either licensing or registration:

o Sharon is the officer dedicated to process licence renewals and

o Peter is the officer dedicated to process car registrations.

 Sharon processes a licence according to a normal distribution with a mean of 5.0 minutes and a standard deviation of 1.0 minute. 

 Peter processes a registration according to a uniform distribution with a minimum of 5.0 minutes and a maximum of 9.0 minutes. 

Complete the following tasks:

1) Draw a flow diagram for the above process.

2) Develop a simulation model using SimQuick software for the peak time period (3-hour time period); perform 400 simulations to determine:

• The overall average waiting time in the process for customers;

• the number of customers served during the 3-hour time peak period;

• the number of customers who have already seen the clerk at the counter but waiting to be served at the end of the 3-hour peak period;

• the utilisation of these three employees, i.e.

o The clerk at the counter

o Sharon

o Peter

If the management is considering adding a new trained officer, Monica, who can renew licences as well as process car registration. Monica’s approach is to keep an eye on both the registration and licencing queues and then serves the next person in the longer queue. The amount of time that Monica processes either a licence renewal or a car registration can be approximated by the following distribution

Tasks:

1) Use SimQuick simulation model to decide whether or not the management team should employ Monica.

2) How best should the Marie’s time be utilised if the management team decides to employ her?