Department of Industrial Engineering and Management Systems
College of Engineering and Computer Science
University of Central Florida

ESI5531: Discrete Systems Simulation (Spring 2015)
Discrete Systems Simulation Project Proposal
Student: Felipe Cesar
E-mail: _________@knights.ucf.edu
UCF ID: XXXXXXX

Xtra Gas Station Model:
More revenue through Simulation

Table of Contents
1.

INTRODUCTION .............................................................................................................. 1
1.1.

2.

GAS STATION DESCRIPTION ................................................................................ 1

PROBLEM DESCRIPTION .............................................................................................. 2
2.1.

PROJECT OBJECTIVES ........................................................................................... 3

2.2.

PROPOSED PERFOMANCE MEASURES TO BE EVALUATED ........................ 3

3.

PROPOSED INPUT DATA, DATA SOURCES AND COLLECTION METHODS ....... 4

4.

PROPOSED ALTERNATIVE SYSTEMS DESIGN ........................................................ 5
4.1.
4.2.

5.

PROPOSED DESIGN 1 .............................................................................................. 5
PROPOSED DESIGN 2 .............................................................................................. 6

PROJECT PLAN ................................................................................................................ 7

List of Figures
Figure 1: Xtra Gas Station Physical Layout .............................................................................. 2
Figure 2: Proposed Design 1 ...................................................................................................... 5
Figure 3: Proposed Design 2 ...................................................................................................... 6

List of Tables
Table 1: Perfomance Measures .................................................................................................. 3
Table 2: Input Data and Collection Methods ............................................................................. 4
Table 3: Project Plan .................................................................................................................. 7

PROJECT PROPOSAL

Xtra GAS STATION MODEL: More revenue through Simulation

1.

INTRODUCTION
The idea is to create a Simulation of a Gas Station model that is located in Brazil, for

privacy we are not going to use the real name, for this project we will call the Gas Station as
“Xtra”. Gas Stations in Brazil have one significant difference comparing to Gas Stations in the United States of America. Due the law every Gas Station in Brazil is obligated to have
Employees to pump fuel on Customer´s Cars, so the customer does not have to leave the car while its fuel tank is being filled-up.
As the Xtra Gas Station has lower prices in the fuel due this large scale purchases from the supplier, comparing to the competitors, there are always big lines in the pumps and consequently long waiting times to be served, especially in hush hours.

1.1. GAS STATION DESCRIPTION
The Xtra Gas Station has four kinds of fuel for the customer to choose, Gasoline
(Regular Unleaded), Gasoline with additives (High Octane), Ethanol, and Diesel. It has only one entrance, so the customer can choose the right pump and the fuel needed. Some pumps have more than one option of fuel and some pumps have only one option of fuel, in total there are four pumps in two stations, each station can accept 02 cars at the same time, or one car for each pump available. After the customer is served and their car’s tank are filled-up, they then pay for the amount purchased directly to the employee that served it without leaving the pump because there is not a central Cash Register. The Xtra Gas Station accepts as form of payment, Cash, Credit Card, Debit Card or Checks.
The physical layout of the Xtra Gas Station is illustrated below. The blue arrows shows the path that the customers follow to be served, the orange arrows shows the path that the customers follow to leave the gas station. The Red Bubbles shows the each employee responsible for each pump. There is only one entrance (showing in GREEN) and only one exit (showing in RED) and the customers are served on a first come, first served basis (FIFO).

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PROJECT PROPOSAL

Xtra GAS STATION MODEL: More revenue through Simulation

Figure 1: Xtra Gas Station Physical Layout

2.

PROBLEM DESCRIPTION
As the Xtra Gas Station has lower prices in the fuel due this large scale purchases

from the supplier, comparing to the competitors, there are always big lines in the pumps and consequently long waiting times to be served, especially in rush hours. The worst hours are in the morning when people are going to work and in the evening when people are coming back home. The main problem is that with the long waiting times a lot of people change their minds and look for another gas station instead of wasting their times waiting in line.
Another issue is not having a central Cash Register, as sometimes this process can take a while depending on the form of payment, the pump remains unused while this step in being full filled and may be a queue behind waiting to be served.
By improving the process and decreasing the waiting times the Xtra Gas Station should be able to have its revenue increased, they could use the saved time in the line to stop at the grocery store attached to the Gas Station and increasing even more the revenue.

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PROJECT PROPOSAL

Xtra GAS STATION MODEL: More revenue through Simulation

2.1. PROJECT OBJECTIVES
The goal of the study is to try to minimize the average waiting time that a customer have to deal in hush hours. If this can be achieved, the gas station will obtain a higher throughput, and also increase its revenue. By doing this the customer in overall would be more satisfied. By developing a model of the Gas Station the project will be able to suggest some alternatives to the current system to achieve the main objective.

2.2. PROPOSED PERFOMANCE MEASURES TO BE EVALUATED
In order to start our simulation tests and development of the model we will performance measures according with the table below.
Name

Description/Definition

Units

Significance

Pump 1 to 4

Time spent by customers from arrival to the Tank Seconds pumped. Provides the general performance of Pump 1 to 4

Employee 1 to 4

Time spent by customer from Tank pumped to Seconds
Amount purchased paid.

Provides the general performance of Employee 1 to
4

Percentage of serving
Pump 1 to 4 usage time compared to the Percent total operation time.

Provides the overall performance of Pump 1 to 4

Percentage of serving
Employee 1 to 4 time compared to the Percent usage total operation time.

Provides the overall performance of the payment service to see how much it impacts in the entire process

Table 1: Perfomance Measures

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PROJECT PROPOSAL

Xtra GAS STATION MODEL: More revenue through Simulation

3.

PROPOSED INPUT DATA, DATA SOURCES AND COLLECTION
METHODS
The data collection will be made in the busiest hours, rush hours, from 6pm to 8pm. The

observation will be made through webcams available in the Gas Station online System. The table below provides the input data and data sources that will be observed and calculated.
Name

Description/Definition

Units

Collection Method

Queue Arrival

Time when a customer arrives

Time
(hh:mm:ss)

Observation

Inter-Arrival time of customers Time between each customer arrives Seconds

Calculated between arrival times

Wait time in Queue

Time customer waits in line

Seconds

Calculated between time of arrival and time when it is served on the pump

Pump Arrival

Time for which the customers arrives at the Pump

Time
(hh:mm:ss)

Observation

Tank Pumped

Time for which the Car´s tank is filled-up

Time
(hh:mm:ss)

Observation

Time to Pump Gas

Total time spent by customer for pumping fuel

Seconds

Calculated between the customer arrives at the pump and the tanked is pumped

Payment Start

Time for which the Employee starts the payment process

Time
(hh:mm:ss)

Observation

Payment Complete

Time for which the Employee finishes the payment process

Time
(hh:mm:ss)

Observation

Time to Complete the Payment

Total time spent by customer for processing payment

Seconds

Calculated between the Payment
Start and Payment Complete

Pump Departure

Time for which the customers departs from the Pump

Time
(hh:mm:ss)

Observation

Service Time

Total time spent by customer to pump fuel, pay for the amount purchased and leave the Gas
Station

Seconds

Calculated from the Sum of Time to Pump Gas and Time to
Complete the Payment

customer

Table 2: Input Data and Collection Methods

4

PROJECT PROPOSAL

Xtra GAS STATION MODEL: More revenue through Simulation

4.

PROPOSED ALTERNATIVE SYSTEMS DESIGN
The two proposed designs will try to optimize the employee perfomance and make the

payment process independent from the fueling process to try to reduce the waiting time and maximize the pumps usage.

4.1. PROPOSED DESIGN 1
The first proposed design is shown below. The idea is to create a central Cash
Register with two cashiers which will allow the pump to be free as soon as the fueling process is finished. This will reduce the time which the customer stays parked next to the pump and consequently reducing the waiting time on the queue. The problem with this design is that the Gas Station will need two more employees at the Cash Registers which means more costs.

Figure 2: Proposed Design 1

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PROJECT PROPOSAL

Xtra GAS STATION MODEL: More revenue through Simulation

4.2. PROPOSED DESIGN 2
The second proposed design is intended to reduce two employees from the pumps to balance the two cashiers added in the first proposed design. The simulation will allow us to visualize if this model will be better and faster as the current Gas Station model this way it could maintain the number of employees and also optimize the system and consequently be more profitable increasing the revenue.

Figure 3: Proposed Design 2

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PROJECT PROPOSAL

Xtra GAS STATION MODEL: More revenue through Simulation

5.

PROJECT PLAN
The table below shows a projected plan for this study.
Task Name

Estimated Start Time

Collect Data
Spreadsheet

/

Create

Estimated Completion

03/29

04/03

Develop/Validate Model in
Simio

04/03

04/08

Enter data
Simulation

04/09

04/16

Develop Alternatives in the
Simulation

04/16

04/20

Write Report / Finalize
Paper

04/21

04/30

/

Analyze

Table 3: Project Plan

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