A Summary of Vehicle Detection and Surveillance Technologies use in Intelligent Transportation Systems

Chapter 2 - Methods and Approach

To accomplish the objectives outlined in Chapter 1, a multi-task approach was taken using a team of experts from Southwest Technology Development Institute (SWTDI), the Vehicle Detector Clearinghouse (VDC), and Dr. Lawrence A. Klein, a private consultant in the traffic management and sensor technology areas. The following sections discuss briefly the tasks performed to complete the objectives of the project.

Collection of Product Information

Product information for vehicle detection and surveillance technologies used in ITS was obtained from the vendors and manufacturers of the equipment. To facilitate this effort, a database of vendors' and manufacturers' addresses and contact information was developed in electronic format using the Excel® worksheet software package. The information for the database was gathered from the following sources:

• Existing VDC product database;
• List supplied by FHWA;
• List supplied by private consultant;
• Internet based searches using key words;
• Intelligent Transportation Society of America's Tenth Annual Meeting and Exposition Official Exhibitor Directory; and
• Traffic Technology International, April/May 2000 issue.

Once the database of vendor and manufacturer information was compiled, vendors and manufacturers were contacted to obtain specific information on their products. The vendors and manufacturers were sent a vendor survey and a cover letter explaining the purpose of the survey. The vendors and manufacturers that were selected were contacted by regular mail, facsimile, and Email. The database included a "status" column that provided updated information, such as whether the vendor survey response was received from the corresponding vendor/manufacturer or whether it was returned unopened. If the survey packet was returned unopened, the address was verified and corrected if necessary and a second packet was sent.

At the time the first edition was prepared, a total of 86 additional vendor survey packets had been sent; thus more responses were expected. The survey responses included product name, a general description of the equipment, sensor technology and configuration, installation time and requirements, product capabilities/functions, recommended applications, list of users, etceteras.

VDC project consultants reviewed the vendor's and manufacturer's survey responses for errors. When necessary, VDC project consultants contacted the vendors and manufacturers to obtain clarification on some of the vendor survey responses.

Collection of User Information

User information was obtained from compiled responses to the State Equipment Questionnaire and the Survey of Degree of Satisfaction of State DOT Personnel with Vehicle Detection Equipment for the ongoing VDC project. Although the user data collected were specific to the make and model of certain types of equipment, generalizations were made based on equipment types so as not to unfairly criticize vendors and manufacturers. The generalizations were then included in this summary document in the equipment description sections.

Compilation of Information

Once a response to the vendor and manufacturer survey was received, it was compiled in electronic format and added to The Summary of Vehicle Detection and Surveillance Technologies Used in Intelligent Transportation Systems document. In order to avoid misinterpretation of vendor and manufacturer information, the vendor survey information was entered directly into an electronic survey form identical to the one the vendor or manufacturer had filled out. The vendor and manufacturer survey responses were organized according to the type of sensor technology utilized (e.g., road tubes, piezoelectric, load cell, bending plate, capacitance mat, inductive loops, magnetometers, video image processor, microwave or laser radar, passive infrared, ultrasonic, or passive acoustic).

In addition to the vendor and manufacturer two-page survey responses, a description of each sensor technology was provided. The description included principles of operation, typical uses, relative costs, advantages and disadvantages, and other pertinent information. Also, in Chapter 3, a comparison of several technologies based on cost, applications, and other factors was presented.

Finally, the information was compiled and organized into a three-ring binder format to allow for quick removal and addition of outdated and updated information, respectively, with the most current version of the document available in electronic format at the following URL: http://www.nmsu.edu/~traffic/. The hard copy version of the document does not have page numbers on the vendor and manufacturer survey responses; thus when these are taken out or added to the binder, the table of contents will remain undisturbed. The authors felt that the information contained in this summary document would be useful to a wide audience having varied technical or managerial backgrounds and different needs or applications.