Highway Traffic Monitoring System

Senior Design May05-06




Faculty Advisors

Professor John Lamont

Professor Ralph Patterson III

Duane E. Smith, P.E., Associate Director for Outreach, CTRE

Team Members

Ben Armfield, CprE

Joel Cardo, CprE

Wendell Cotton, EE

Brent Duppong, EE


DISCLAIMER: This document was developed as a part of the requirements of an electrical and computer engineering course at IowaStateUniversity, Ames, Iowa. This document does not constitute a professional engineering design or a professional land surveying document. Although the information is intended to be accurate, the associated students, faculty, and IowaStateUniversity make no claims, promises, or guarantees about the accuracy, completeness, quality, or adequacy of the information. The user of this document shall ensure that any such use does not violate any laws with regard to professional licensing and certification requirements. This use includes any work resulting from this student-prepared document that is required to be under the responsible charge of a licensed engineer or surveyor. This document is copyrighted by the students who produced this document and the associated faculty advisors. No part may be reproduced without the written permission of the senior design course coordinator.

April 28, 2005


Table of Contents

List of Figures

List of Tables

List of Definitions

Section 1 - Introductory Materials

1.1Executive Summary


1.3Problem Statement

1.3.1General Problem Statement

1.3.2General Solution Approach

1.4Operating Environment

1.5Intended Users and Uses

1.5.1Intended Users

1.5.2Intended Uses

1.6Assumptions and Limitations

1.6.1Initial Assumptions List

1.6.2Initial Limitations List

1.7Expected End-Product and Other Deliverables

Section 2 - Approach and Product Design Results

2.1Approach Used and Progress Results

2.1.1Design Objectives

2.1.2Functional Requirement

2.1.3Design Constraints

2.1.4Technical Approaches, Considerations and Results

2.1.5Complete System Comparison

2.1.6Testing Approach Considerations

2.2Recommendations Regarding Project Continuation

2.3Detailed Design

2.4Implementation Process

2.5End-Product Testing

2.6Project End Results

Section 3 - Resources and Schedules


3.1.1Personnel Effort Requirement

3.1.2Other Resource Requirements

3.1.3Estimated Financial Requirements


3.3Project Schedule

3.4Deliverables Schedule

Section 4 - Closure Material

4.1Project Evaluation


4.3Additional Work

4.4Lessons Learned

4.5Risk Management

4.6Project Team Information


4.6.2Faculty Advisors

4.6.3Student Team Information

4.6.4Project Website

4.7Closing Summary


List of Figures

Figure 1 - Diagram of basic process flow

Figure 2 - Map of the primary exit to be examined

Figure 3 - Layout of system

Figure 4 - West bound traffic approaching the Elwood Drive Exit 146

Figure 5 - Exit 146, the primary location for system equipment

Figure 6 - Original project Gantt chart

Figure 7 - Revised project Gantt chart

Figure 8 - Actual project Gantt chart

Figure 9 - Estimated deliverables Gantt chart

Figure 10 - Actual deliverables Gantt chart

List of Tables

Table 1 - Original personnel effort requirements estimate (hours)

Table 2 - Revised personnel effort requirements estimate (hours)

Table 3 - Actual personnel effort requirements (hours)

Table 4 - Original other resource requirements

Table 5 - Revised other resource requirements

Table 6 - Actual other resource requirements

Table 7 - Original estimated financial requirements

Table 8 - Revised estimated financial requirements

Table 9 - Actual financial requirements

List of Definitions

Center for Transportation Research and Education (CTRE) - Performs transportation research for public and private agencies and companies; manages its own education program for transportation students; and conducts local, regional, and national transportation services and continuing education programs.

Code division multiple access (CDMA) (or “spread spectrum”) - A form of multiplexing where the transmitter encodes the signal using a pseudo-random sequence which the receiver also knows and can use to decode the received signal. Each different random sequence corresponds to a different communication channel. This technology is used for wireless digital data transfer.

Department of Transportation (DOT) - The United States federal department that institutes and coordinates national transportation programs; created in 1966.

Highway traffic monitoring system (HTMS) - This name and acronym refer to the system which the team will be designing.

Inductive loop - A coil of wire embedded in pavement that detects the change in inductance when a vehicle drives over it.

LED - A light emitting diode is an electrical component that emits light.

Light beam - Sensor that detects an object’s presence by detecting the interruption of a light beam.

Motion detector - Sensor that detects the heat of an object near it. It does this by the change in infrared light created from the change in heat.

PLC -Programmable logic controller. A device used toautomate monitoring and control of a system. It receives input, performs a series of logical operations, and provides a signal output.

RF transmitter/receiver - Radio frequency spectrum transmitter or receiver.

Spread spectrum - Refer back to CDMA.

Tape switch - A sensor that has two conductive plates separated by a small distance. When an object presses the plates, they touch together and close the circuit.

Wire loop - Refer back to inductive loop.


Section 1 - Introductory Materials

The introductory materials section contains the executive summary, acknowledgements, problem statement, operating environment, intended users and uses, assumptions and limitations, and expected end-product and other deliverables.

1.1Executive Summary

The main purpose of this document is to convey to the reader the project goal and the outcome of the project. The following paragraphs briefly describe what the project is about and what information is contained in the document.

Traffic accidents often occur when a major athletic event or concert is held at IowaStateUniversity. This is a result of drivers not being able to observe traffic that is backing up in hard-to-see locations. The Elwood exit off of west-bound US Highway 30 is one such example. The objective of this project was to develop a portable system that could detect slow moving or stopped traffic and then alert approaching drivers. The design incorporates speed and proximity sensors, a control system, and a display system, see Figure 1 for an example. The traffic monitoring system was designed to help prevent such accidents and increase traffic flow during these events. A fully operational system would be able to save thousands of people travel time, reduce costly vehicle accidents and possibly save someone's life.

Figure 1- Diagram of basic process flow

This document presents a condensed version of the work that has been done in order to complete the project. A portion of the document covers the research accomplished. In order to condense the amount of material in this document the detailed selection of the sensor technology, control systems technology, communications technology, and display systems technology, including such important details as to why a specific technology was selected and how much the technology costs, can be referenced in the System Proposal Appendix B-E.

The time that has been spent on individual aspects of this design isincluded, also contained in this document are the estimated, revised, and actual work hours for specific tasks that were established at the beginning of the project. Finally, there is a progress report that details what tasks have been completed and to what future work could be done.


The design team would like to thank our faculty advisors; John Lamont, Ralph Patterson and Duane Smith. In addition to our advisors we would also like to thank Willy Sorenson of the Iowa DOT for his assistance in this project. They have greatly assisted the team by donating their time and technical advice. Their support is deeply appreciated.

1.3Problem Statement

The two following sections are a more detailed description of the executive summary from Section 2.1. The problem will be presented in more detail and the solution approach will be given.

1.3.1General Problem Statement

When there are special public events that a large number of people attend, particular traffic problems occur. For IowaStateUniversity, these events include major sporting events and large concerts. They often occur at Jack Trice Stadium and at the IowaStateCenter which includes Hilton Coliseum and Stephens Auditorium. All of these facilities are located off of Elwood Drive.

The problem the team presents a solution for starts before an event begins. There is a large inflow of traffic to the facilities which causes traffic to slow down and back-up on Elwood Drive. Because this is the major access road for people coming off of U.S. Highway 30 (see Figure 2), there is a major safety concern. Vehicles that are traveling at highway speeds are encountering slow moving or stopped vehicles on Highway 30 or the Elwood Dr Exit off of it. Visibility in the area is low due to the exit being located on the backside top of a hill. Because of this, there is an increased risk that drivers may collide with stopped cars as they approach the exit at high speed.

Figure 2- Map of the primary exit to be examined

This is a specific area where the problem occurs, but this type of situation can be found at many other intersections and in many other towns. The problem that the team has been presented with is the development of an automated system that can inform people of these unusual traffic conditions before it is too late. The Ames location is used as an example, but the team’s solution is adaptable to work at other similar intersections.

1.3.2General Solution Approach

In order to address these problems, a system was designed to inform highway drivers of unusually slow or stopped traffic ahead. The system consists of a group of light beam sensors placed at the intersections of Highway 30 and Elwood Drive, I-35 Southbound and Highway 30, and I-35 Northbound and Highway 30. The sensors connect to a control system that receives a signal after each light beam is broken. The control system then determines the vehicle’s speed by detecting the time it takes the vehicle to travel between the two sensors. Once a predetermined number of slow vehicles are detected, the controller then communicates to a wireless communication device that transmits a message to activate a sign warning drivers to slow down. After a predetermined number of fast vehicles are detected, the controller then sends a signal to the wireless communication device to deactivate the sign letting drivers know that traffic ahead is flowing normally. Many technologies were considered in order to find the system of sensors, controller and display devices that were most cost effective at alerting drivers of the increased danger.

Figure 3-Layout of system

1.4Operating Environment

The final system is portable and must endure the shock and motion that are associated with moving equipment. Since it operates outdoors the system needs to withstand the outdoor temperature extremes and survive adverse weather conditions. Therefore, moisture, impact, and wind resistance were also considered. Since the system is designed to be near or on the shoulder of a road, it therefore needs to be safely positioned and identified so that additional traffic problems will not be caused.

Figure 4- West bound traffic approaching the Elwood Drive Exit 146

Figure 5- Exit 146, the primary location for system equipment

1.5Intended Users and Uses

The following two sections include information about the intended uses and users for the Highway Traffic Monitoring System.

1.5.1Intended Users

This system is designed to be operated by trained event staff, Department of Transportation staff or Highway Patrol Officers. To accomplish this, the system was designed to be relatively easy to setup, use and take down. Staff members should be familiar with how to operate and troubleshoot the system before they install or set the system up.

The traffic monitoring system is going to be used by motorists, so the warning messages and traffic information were selected accordingly.

1.5.2Intended Uses

This is a highway traffic monitoring system. Therefore, it is designed tobe used on highspeed roads. It is not designed to function on low traffic, slow speed streets, because there is not enough traffic to warrant a system in these areas. The system was designed to monitor traffic on a single roadway that has as many as three feeding roadways. The system is primarily designed to work forIowaStateUniversity’s Elwood Exit problem area, but the design is flexible so that it can be adapted for use at other locations.

1.6Assumptions and Limitations

The two following sections are lists of the assumptions and limitations that wereincluded in the planning.

1.6.1Final Assumptions List

  • A single roadway is monitored
  • No more than three feeding roadways are allowed
  • The maximum warning distance is 2 miles
  • Initially designed for Highway 30 onto Elwood Dr. (exit 146)
  • No rerouting of traffic is considered with design
  • DOT or ISU employees will install equipment

1.6.2Final Limitations List

  • Current DOT electronics signs may be used for testing (if applicable)
  • System is able to be removed and stored when it is not needed
  • System is able to be setup to work in different locations
  • System is able to withstand outdoor temperature and weather extremes
  • System is able to distinguish between moving and stopped traffic
  • System is able to operate in a high traffic area
  • System is able to operate for a minimum of 6 hours
  • System is able to be setup in no more than one man hour
  • System is capable of monitoring two lanes of traffic simultaneously

1.7Expected End-Product and Other Deliverables

The end-product of this project was dependent upon available funding and design time requirements. Possible end-products included:

Design proposal - A full design proposal report

This end-product will be completed. It should not require outside funding and is the most possible to accomplish in the amount of time the team can allot for this design project. A full design report will be provided including controller logic, communications setup, system component location maps, parts and cost lists and assembly and operations information. Schematic designs, computer system requirements, processor specifications and hardware specifications will be included in the design. A demonstration may be part of the overall design presentation.

Simulation - A working bench-top system

The simulation could go beyond the full design report and could include a controller that communicates with one or more sensors and one or more display devices. It is less costly than a full prototype, but still requires significantly more funding than currently is available. Outside funding will need to be found (potentially from the DOT).

Prototype - A fully working testable system

This would be the most difficult and costly to produce. Outside funding would need to be found (potentially from the DOT). DOT equipment would also need to be loaned to the team. In addition to the complete system design, the team would assemble and test the equipment to make a functional traffic monitoring system. Considerable time will also need to be spent in obtaining funding, purchasing parts and working with individuals from the Highway Patrol, DOT and ISU.

End-Product Selection

The most feasible end-product to develop was the design proposal. This was due to the cost effectiveness and time constraints of the design. The 150 dollar budget allotted to this project would have been exhausted on a single sensor. Much more fundingwould have been needed to be obtained in order to implement a simulation or a prototype.

Section 2 -Approachand Product Design Results

Section 2 contains detailed information on the approach and design for this project. The approach that has been used for the solution of the proposed design problem is described. With this approach information and status, the design and the direction for the continuation of the design process will also be stated.

2.1Approach Used and Progress Results

Included in this section are the design objectives, functional requirements, design constraints, technical approaches, technical considerations, technical evaluation results, testing approach considerations and recommendations regarding project continuation or modification.

2.1.1Design Objectives

Several criteria were identified as necessary objectives the system needed to meet. These criteria are detailed below.

Low cost: The system should be affordable for ISU and the DOT. Keeping the price as low as possible was the major consideration for the project. The more functional the system the higher the overall cost would be. Considerations for cost included installation fees, eminence costs, assembly costs, and the costs for the components used. The cost of the overall system was a major driving factor behind the technological considerations.

Near real time monitoring: The system must be able to monitor traffic in a real time manner. The data analysis did not need to be done in real time, but needed to be done as close to real time as possible. The faster the system can analyze data, the faster it can warn motorists of impending problems. Real time monitoring directly affects power consumption and communication requirements.

Reliable operation: The system must be able to operate reliably for up to six hours at a time. The system must be able to handle any errors presented to it and reliably output dependable results. Reliable operation will depend mainly on power consumption and effectiveness of the detection scheme that will be employed.

2.1.2Functional Requirement

The requirements the system needed to meet to be considered a success are detailed below.

Capture and analyze: The primary goal of the system was to detect the presence of a vehicle and the speed of the vehicle. The analysis of the speed of the vehicle could be done either by the sensor itself, or by a software system located elsewhere. The system needed to be able to detect whether a car was present or not. All other measurements fail if this primary objective is not met.

Communication control system: The system needed to be able to transmit the data collected to a control system that would then either analyze the data, transmit the data to a software system for analysis, or directly activate a system to notify motorists.

Notify motorists: The system needed to be able to warn motorist of impending traffic problems. This can be achieved in a number of different implementations. The notificationcould have been either a visual warning from a road side traffic sign, or an auditory warning via a radio frequency, or a combination of the two. The main consideration needed to be the amount of warning time for a driver to understand that there was a problem ahead and be able to react to the problem.