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As a newly developing idea, more and more information is becoming known about OBD-III. Below are some frequently asked questions regarding OBD-III. This is not an all-encompassing list, but a start into understanding the basics of OBD-III. For your convenience, refer to the easy-to-use menu of items found here.


A program to minimize the delay between detection of an emissions malfunction by the OBD-II system and repair of the vehicle

Two basic elements:

  • Read stored OBD-II information from in-use vehicles.
  • Direct owners of vehicles with fault codes to make immediate repairs


Three ways to send/receive data:

  • Roadside reader
  • Local station network
  • Satellite


  • Incorporate into biennial I/M program
    • Read fault code to screen for vehicles that need complete testing
    • Pass or short test for vehicles with no fault code
  • Does not speed up repair process
  • Out-of-cycle inspection
    • Compile and screen data
    • Mail notice to vehicle owner requiring out-of-cycle inspection within 10 days
    • Require Certificate of Compliance (C of C) on next registration/resale, or
    • Require C of C within 30-60 days, with citation for noncompliance
    • Enforce citation via court and/or DMV penalty at next registration
  • Roadside Pullover
    • CHP flags down vehicles with fault codes
    • Technician verifies problem by inspecting and/or testing vehicle
    • Issuance of notice requiring out-of-cycle inspection
    • Same enforcement (C of C /citation)


  • OBD-III imposes sanctions based on "suspicionless mass surveillance" of private property
    • Random, possibly frequent testing
    • No advanced knowledge vehicle will be tested
    • Results of testing not immediately available (unless roadside pullover follows)
    • No opportunity to confront or rebut
    • Possible use of system for other purposes (Police pursuit/immobilization, tracking, cite speeders)
  • OBD-III raises 4th Amendment search and seizure privacy issues:
  • ''The right of the people to be secure in their persons, houses, papers and effects, against unreasonable searches and seizures shall not be violated...'' (emphasis added; also see Art. I, Sec. 19 of Calif. Constitution)
  • From legal perspective, it is unprecedented: previous cases have looked at surveillance of individuals

ARB Request For Proposals

Incorporation of Radio Transponders into Vehicle On-Board Diagnostic Systems

The Air Resources Board reserves the right to reject any proposal deemed nonresponsive to the RFP, not responsible, and/or not reasonable.

Proposals submitted under this RFP will be evaluated by the "secondary" method, in which the cost of the proposed research is an important, but not a determining, factor in the awarding of the contract.


The objective of this study is to demonstrate the feasibility and cost effectiveness of replacing the current emissions-based periodic Inspection and Maintenance (I/M) program with automated inspections based on the OBD-II system and an on-vehicle radio transponder. The study will test, evaluate and demonstrate the viability and cost of equipping new vehicles with various transponder technologies and assess how these technologies can be effectively used to improve the convenience, effectiveness, and cost-effectiveness of the I/M program.

Perhaps the most serious drawback in California's current I/M program is the fact that the entire vehicle fleet must be tested in order to identify the relatively small number of vehicles that are likely to fail. Currently, approximately ten million vehicles per year are required to undergo an I/M inspection that results in passing scores for 70 percent of the vehicles. The pass rate is expected to improve to perhaps 90 percent as vehicles with more durable emission control systems enter the fleet. Californians spend in excess of $168,000,000 per year having clean cars tested. If the inspection process could be automated through the use of transponder-assisted on-board diagnostic systems (in what could become an OBD-III requirement or program), the process could be made less costly and time-consuming: only those vehicles with actual problems, as indicated through the presence of codes stored in the OBD-II system, would be required to undergo a full inspection.

In this study, the contractor will evaluate how inspections of radio-transponder equipped vehicles could be performed, taking into account effectiveness, cost, convenience, and public reaction. Special attention shall be given to assessing and addressing privacy concerns involving the use of transponders. The contractor will fully assess at least one concept involving periodic inspections of transponder-equipped vehicles, and shall assess at least one non-periodic based inspection concept if according to its assessment that would be as effective and more cost-effective than periodic inspections. The contractor will procure and install appropriate transponders on several OBD-II-equipped vehicles and demonstrate the viability of performing transponder-based inspections. Based on the demonstration, the contractor will compare the effectiveness, cost, and time of transponder-based inspections to the current enhanced I/M program.


As stated above, some $168,000,000 per year is spent in the I/M program to test vehicles that subsequently pass the inspection. While recently adopted enhancement to the program will result in a substantial improvement to the program's effectiveness for vehicles that fail, the costs of inspection are also projected to increase for both passing and failing vehicles. This situation is further complicated by the fact that improvements in vehicle durability are projected to further decrease the percentage of failing vehicles in the future. Although several approaches are being

incorporated into the new I/M program that are designed to pre-screen the fleet for passing and failing vehicles (i.e., High Emitter Profile and Remote Sensing Devices), no provisions are currently in place to exempt "clean" vehicles from inspection.

In 1989, the ARB adopted regulations requiring the installation of sophisticated on-board diagnostic systems beginning with the 1994 model year (OBD-II). By 1996, all new passenger cars and light- and medium-duty vehicles certified for sale in California will be required to have OBD-II systems that require the illumination of a malfunction indicator light (MIL) when malfunctions occur that are likely to result in emissions that exceed 1.5 times the vehicle's certification standard. As emissions standards values are reduced in future model years, more accurate and more sophisticated monitoring systems must be developed. Whereas Remote Sensing relies upon a several-millisecond snapshot of emissions, the constant monitoring of emissions-critical components by the OBD system may obviate the need to perform traditional emissions tests of vehicles so equipped.


Task 1 - Assessment of inspection options.

Currently, California's Inspection and Maintenance Program requires the inspection of all vehicles at least once every two years. Some portion of the fleet, however, because of change of ownership or identification of gross emissions, may undergo more frequent inspection. In this task, the contractor shall evaluate a number of inspection options of transponder-equipped vehicles based upon the estimation of the effectiveness, cost-effectiveness, and convenience of each option relative to the current enhanced periodic inspection requirement.

The overall objective of this task is to identify the most promising approaches, at least one periodic and one non-periodic, utilizing the automated inspection capabilities afforded by transponder-equipped vehicles. Possible approaches include performing the automated inspection at licensed inspections stations and/or as part of the periodic maintenance servicing performed at automobile dealerships, or performing the inspections non-periodically at stand-alone kiosks or gasoline service stations. In proposing possible alternatives to traditional periodic inspections, the contractor will be required to thoroughly assess public reaction, possible privacy issues, and the likelihood of public acceptance for each approach studied. As part of this assessment, the contractor shall evaluate how a driver-controlled activation switch might impact program effectiveness.

Several entities, including government agencies and private industry, are currently pursuing the use of radio transponders in vehicular applications. In light of the fact that cooperative research in this area may lead to a more cost-effective system and increase public acceptance, the contractor shall also investigate the possibility for coordination with other entities and the identification of possible conflicts between this project and any other project planned or currently underway.

Task 2 - Procurement and instrumentation of test fleet.

In this task the contractor shall procure five OBD-II-equipped vehicles and outfit each (as described below) with radio transponders that have been procured or fabricated by the contractor. One of the five vehicles will be supplied to the selected contractor by the ARB, and thus bidders should only budget for procurement of four vehicles. Multiple vehicles are required to resolve any issues of signal collision between the reader and two or more vehicles attempting to respond to an automated query.

Bidders must provide a list of eligible makes and models and their strategy for the most cost-effective method of obtaining these vehicles for this project. It is preferred that a mix of foreign and domestic vehicles be procured in order to address the relative ease or difficulty of systems integration. ARB staff approval shall be obtained prior to vehicle procurement. Proposals must also specify the explicit method of obtaining the vehicles (rental, lease, etc.) and estimated costs. The purchase of vehicles as "Equipment" is discouraged because of vehicle selection limitations imposed by the State procurement process.

The contractor shall procure or fabricate five (5) transponder systems and two (2) receivers having the capabilities described below:

The transponders shall have the capability of storing and transmitting the full 17-digit vehicle identification number (VIN) of the vehicle in which it is installed.

The transponders shall transmit the presence of emissions faults and the actual fault code numbers stored in the OBD-II system.

The transponders shall transmit a status code indicating "OK", or a trouble code indicating that the integrity of the system has been compromised or that the power supply is low (or disconnected). This status code shall be transmitted whenever the system is queried.

The physical dimensions of the transponders should allow for installation in either the engine compartment or behind the dashboard. The desired dimensions of the complete system are not to exceed that of a pack of cigarettes (about 1" x 2 _ " x 3 _").

Whether the transponder system is to be mounted in the engine compartment or behind the dash, the contractor shall ensure that the transponder operates reliably during extreme operating conditions which are typical in vehicular applications, including high temperature, high humidity, and vibration.

The transponder systems should be designed to use the vehicle's power supply, but should also incorporate a method to prevent loss of information and to store (and transmit when queried) a trouble code if the vehicle's battery fails or is disconnected. Bidders shall discuss how the transponder system will be integrated with the existing battery re-connect strategies (i.e., disconnecting the vehicle battery for more than a short period of time typically resets many vehicle parameters --including trouble codes--to default values).

The contractor shall address the issue of system and data security, specifically in the area of tamper-proofing of transponders. The proposal should suggest how the systems can be made as "tamper-proof" as possible. As defined here, tampering includes erasing trouble codes, overriding the OBD system, and sending out fake and/or false codes. Bidders shall also note to whom the security measures would be aimed (ordinary consumers, typical mechanics, specialty parts manufacturers, etc.).

The transponder signal receivers shall be capable of performing these functions:

Querying a specific vehicle that is in close proximity to similarly equipped vehicles without signal collision.

Storing a query and received data in a database format. Data stored will include:

  1. A.Date and time of current query
  2. B.Date and time of last query
  3. C.VIN
  4. D.Status ("OK", "Trouble", or "No response")
  5. E.Stored Codes
  6. F.Receiver station number

"COOPERATIVE TECHNIQUES" For Police Pursuit/Mobilization

The cooperative techniques comprise devices that are installed on automobiles. These devices would receive a coded radio frequency signal that would produce a progressive speed reduction or shut down the automobile. The speed reduction and shut down could be incorporated in the On-Board Diagnostic (OBD) III system that is planned for implementation in the year 2000 and later. This system is planned to have a radio transponder for reading out automobile status including vehicle number and smog equipment fault codes.

The major obstacle to overcome is to get public acceptance of a device that they have to pay for and that can disable their automobile. One way to obtain public acceptance may be to offer incentives by including this device as part of a package that provides other benefits. These benefits could be an anti-theft device and/or a smog readout device. The smog readout device could eliminate the need for costly and time-consuming periodic inspections at smog stations. With the idea that the only time you would need to go to an inspection station is when the automobile exceeds smog-generating limits.

In addition to public acceptance, this approach will require federal government, state government and car manufacturer cooperation.

The use of a cooperative device has strong appeal because of effectiveness, safety and ease of use. Incorporating the overall system as part of a larger subsystem would reduce cost and make it more attractive.


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