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    <title>Transport Research International Documentation (TRID)</title>
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    <copyright>Copyright © 2026. National Academy of Sciences. All rights reserved.</copyright>
    <docs>http://blogs.law.harvard.edu/tech/rss</docs>
    <managingEditor>tris-trb@nas.edu (Bill McLeod)</managingEditor>
    <webMaster>tris-trb@nas.edu (Bill McLeod)</webMaster>
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      <title>Transport Research International Documentation (TRID)</title>
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      <link>https://trid.trb.org/</link>
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      <title>HARMONIZATION OF BRAKING REGULATIONS - REPORT # 5: TESTING FOR DEVELOPMENT AND EVALUATION OF THE SUPPLEMENTAL NOTICE OF PROPOSED RULEMAKING ON HARMONIZATION OF PASSENFER CAR BRAKE STANDARDS. FINAL REPORT</title>
      <link>https://trid.trb.org/View/305956</link>
      <description><![CDATA[Testing has been conducted to support the development of a new passenger car braking regulation (FMVSS 135).  In particular, it describes tests that were run to address comments on the severity of the fade test as specified in the first Notice of Proposed Rulemeking (NPRM) for FMVSS 135 and tests that were run to evaluate the test procedures and performance requirements in the supplemental Notice of Proposed Rulemaking (SNPRM).  Four vehicles were utilized in the fade test severity evaluation and nineteen vehicles were tested to the SNPRM procedures.  These nineteen cars were also tested to the current passenger car brake standard (FMVSS 105) and to a procedure for determining adhesion utilization (brake balance) properties.]]></description>
      <pubDate>Fri, 31 Aug 1990 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/305956</guid>
    </item>
    <item>
      <title>HOW TO SOLVE FIVE TOUGH BRAKE PROBLEMS</title>
      <link>https://trid.trb.org/View/270676</link>
      <description><![CDATA[This article discusses the potential causes of five tough brake problems that occur with some frequency and provides the home mechanic with general guidelines for the repair of these brake malfunctions.  These five problems are: (1) a brake-system malfunction which causes the car to pull to one side; (2) a pulsating brake pedal; (3) brake squeal; (4) a brake pedal that goes to the floor or almost to the floor and then "pumps up" to a normal position after repeated applications; and (5) no brake lights.]]></description>
      <pubDate>Fri, 31 Jan 1986 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/270676</guid>
    </item>
    <item>
      <title>LINING LIMITS</title>
      <link>https://trid.trb.org/View/202484</link>
      <description><![CDATA[This article tries to answer questions about replacement brake lining quality.  It considers friction codes, resistance to fade, wear, noise, resistance to effects of water, friendliness to drums and rotors, lining quality and lining identification.  It includes several charts and photos and an insert: "Brake Lining Scorecard."]]></description>
      <pubDate>Mon, 30 Apr 1984 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/202484</guid>
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    <item>
      <title>WHY AN AIR DISC BRAKE?</title>
      <link>https://trid.trb.org/View/193678</link>
      <description><![CDATA[A ten-year investigation of commercial vehicle disc brakes indicates that potential revenue gain due to reduced truck weight with air disc brakes is illusionary. Initial cost, service cost, service parts availability, need for high skill service labor, and extreme mechanical wear susceptibility as well as lining wear negate any savings from using air disc brakes instead of cam brakes.  Air disc brakes presently provide no real improvement in overall performance or safety.  With time, brake output consistency decreases and "feel" suffers.  The ability of the brake to provide good life under extreme operating conditions with minimum mechanical service is doubtful.  "Looseness" necessary to preclude caliper bind results in taper lining wear, and energy load transfer between dissimilar brakes on a tractor-trailer can also produce excessive wear. The apparent fade resistance of disc brakes can be a safety hazard due to sudden, unexpected brake failure. Brake type intermix aggravates this situation and also adversely affects rig stability.  Air disc brakes are not currently suitable for general use because of their relatively high initial and long-term cost and marginal performance and wearability.]]></description>
      <pubDate>Mon, 30 Jan 1984 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/193678</guid>
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    <item>
      <title>AIR DISC BRAKES--CONSIDERATIONS AND CONCERNS</title>
      <link>https://trid.trb.org/View/193680</link>
      <description><![CDATA[Demonstrated advantages of the air disc brake include: improved side to side balance (reducing pulls and requiring less driver control), fade resistance, improved water recovery, less torque variation with speed, and reduced weight.  The "productivity" of the brake is judged by such cost factors as initial cost, service, reline interval, reline cost (time and material), and cost of other components, none of which are totally quantifiable by accepted industry standards.  Due to its different design, disc brake performance differs from that of a drum brake in single and multiple stops and in continuous input types of operations typified by mountain grades. Brake balance is a major concern, as affected by brake type intermix (Federal Motor Vehicle Safety Standard 121 and pre-121 equipment), push-out pressure (chamber return springs), and absence of shoe return springs. Friction materials for the air brake are relatively new in their development in view of the brake's uncertain market potential.  Other air disc brake concerns are the change of bearing load (highly directional in nature) and potentially higher drag (lower fuel economy).  The compatability problem of disc and drum brakes needs to be resolved, both by design and by extensive testing and tuning.]]></description>
      <pubDate>Mon, 30 Jan 1984 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/193680</guid>
    </item>
    <item>
      <title>MARKET PROSPECTS FOR AIR DISC BRAKES IN HEAVY TRUCKS</title>
      <link>https://trid.trb.org/View/193682</link>
      <description><![CDATA[From the perspective of the heavy-truck operator, the pros and cons of air disc brakes are compared with those of other air brake types (S-cam drum, wedge drum). Market prospects for the air disc brake are evaluated, including specific forecasts.  The primary advantage of the air disc brake over the drum brake are better fade resistance, greater stability, lighter weight than the S-cam, and ease of maintenance.  Disadvantages include greater initial cost, lack of field experience, and front axle weight slightly more than the S-cam. Cost of ownership (purchase price, replacement part cost, maintenance time for reline, lining and rotor life, payload, and resale value) is the key to broad market acceptance, and lining life is a major open issue.  If cost of ownership factors do not significantly offset the premium price of air discs, demand will be limited to weight and performance sensitive users (about 30,000 trucks annually by 1985).  With more competitive cost of ownership, annual volume could reach 70,000 trucks by that year.]]></description>
      <pubDate>Mon, 30 Jan 1984 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/193682</guid>
    </item>
    <item>
      <title>AIR DISC BRAKES: A TRUCK MANUFACTURER'S VIEW</title>
      <link>https://trid.trb.org/View/193683</link>
      <description><![CDATA[Kenworth Truck Company has installed air disc brakes on some 500 trucks and truck-tractors over the past four years.  The brakes are offered as an unpublished option only, to encourage the customer to make a well-considered choice for air disc over drum brakes, to indicate the experimental nature of the air discs, and to place more engineering attention on each application.  The customers rank weight savings and serviceability as the most important advantages.  Improved fade resistance ranks next and seems to appeal to two customer types: the safety-conscious operator, and the operator who wants to improve productivity through reduced trip times (generally West Coast loggers).  Improved stability with air discs is not a major customer concern. Excessive wear is the number one problem, caused either by incompatibility of air discs with other brake types or by unintentional driver abuse.  Squeal and chatter have also been sources of customer complaints.]]></description>
      <pubDate>Mon, 30 Jan 1984 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/193683</guid>
    </item>
    <item>
      <title>AIR DISC BRAKES--EARLY EXPERIENCE IN FIRE APPARATUS</title>
      <link>https://trid.trb.org/View/193684</link>
      <description><![CDATA[For firefighting equipment, a four-wheel air disc brake system offers the functional attributes of stability, driver controllability, and resistance to adverse road conditions.  These features are especially important in view of the range of experience among volunteer fire department personnel.  Large city professional fire department operations can perform more efficiently if fire trucks have self-adjusting brakes such as those used in fire pumpers built by Mack Trucks, Inc.  High fade resistance is another important feature of air disc brakes for such operations. In early experience, most drivers rated full air disc performance as less effective than the previous brake system (air/hydraulic front disc, drum rear).  This is attributed to two factors: front brake power sized to initial Federal Motor Vehicle Safety Standard (FMVSS) 121 stopping distance requirements (which subsequently have been increased or deleted), and disc brake torque curves flatter over time than drum brake curves.  With experience, there has been an increase in drivers' confidence levels.  Less parking brake effectiveness was also experienced initially.  Although FMVSS 121 compliance was established, the static coefficient of friction deteriorated somewhat at elevated temperatures.]]></description>
      <pubDate>Mon, 30 Jan 1984 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/193684</guid>
    </item>
    <item>
      <title>TRUCK AIR DISC BRAKES FROM USERS' POINT OF VIEW</title>
      <link>https://trid.trb.org/View/193685</link>
      <description><![CDATA[Ruan Transport Corp. (tank carrier) supports air disc brakes for trucks because of their vehicle stability during braking, stability with a slopping liquid load, and possibility for weight reduction and easier servicing. In an empty truck, the adverse effect of the excess brake capacity on vehicle stability when braking on slippery surfaces, can be nearly eliminated by the modulating ability and fast release times of air disc brakes.  After over 50,000 mi. in the most severe service, the air disc brakes have presented no problems, and lining life has exceeded that of drum brakes.  The company believes that safety benefits and accident cost reduction will be realized through improved vehicle stability and brake fade elimination.  The adequacy of the salt water spray test is questioned; calcium chloride used in road deicing salts is corrosive even in dry weather and appears more detrimental to automotive hardware than ordinary road salts.  Ruan recommends that automatic slack adjusters be incorporated as part of the air disc brake by the brake manufacturer. Air disc brakes are more tolerant of imbalance, overloading, and misuse; brake life and maintenance costs are sacrificed while fade resistance and vehicle stability are improved.  Better liaison between user and supplier is needed, as well as compatibility between drum air and air disc brakes.]]></description>
      <pubDate>Mon, 30 Jan 1984 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/193685</guid>
    </item>
    <item>
      <title>STRAIGHT AIR DISC BRAKES</title>
      <link>https://trid.trb.org/View/193686</link>
      <description><![CDATA[The major design features, and laboratory and vehicle test development of straight air disc brakes for trucks, tractors, and trailers are described in detail.  The result of development and fleet testing combined with experiences from a heavy-duty truck air-over-hydraulic disc brake produced by Kelsey-Hayes Company since 1975, this brake was designed to provide full automatic adjustment with the mechanism completely sealed; brake sizing directly proportional to brake torque requirements; rotor width and diameter for optimum heat dissipation; full compatibility with drum-braked vehicles; installation on current production front spindles, rear axles, and trailer axles; and use of standard service and spring-applied parking brake chambers with only minor modifications.  Based on lining energy absorption capabilities, two basic brake models were developed: one primarily for front axles, and the other for all truck and trailer rear axles, both single and tandem.  In addition to performance advantages (improved directional stability, increased fade resistance, improved recovery, shorter stopping distances, reduced speed sensitivity, and increased lining and rotor life for most uses), the air disc brake has several advantages over the hydraulic disc brake on trucks equipped with air systems: air only as the actuating medium, utilization of existing wheel end hoses and fittings, no brake bleeding, use of standard trailer air hoses and couplings, compatibility with spring-applied parking brakes, and simplicity in maintenance/service.]]></description>
      <pubDate>Mon, 30 Jan 1984 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/193686</guid>
    </item>
    <item>
      <title>IH (INTERNATIONAL HARVESTER) INTRODUCES HYDRAULIC FOUR-WHEEL DISC BRAKES</title>
      <link>https://trid.trb.org/View/188499</link>
      <description><![CDATA[The development of hydraulic four-wheel disc brakes and their advantages over conventional drum brakes are discussed. International Harvester's (IH) Truck Group and the Bendix Corp. began initial design/computer studies and development work on hydraulic four-wheel disc brakes to meet the requirements of the then-proposed FMVSS 105-75 (Hydraulic Brake Systems). Five years of extensive testing and evaluation (including durability tests, traffic tests, evaluations of improved shielding and wear indicators, corrosion tests, lining comparisons, heat fade tests, water recovery tests, and maintenance tests) have resulted in the availability of IH hydraulic four-wheel disc brakes on IH medium-duty truck and school bus chassis. These brakes have several advantages over conventional hydraulic drum brakes. They allow 50% of the braking effort by the front axle, and 50% by the rear axle, rather than the 30%/70% ratio of conventional drum brakes which often causes premature lock-up and poor directional stability under limited traction or lightly-loaded conditions. The new IH brakes also provide straighter, improved control stops with better modulation and less "wheel fight" for the driver. The increased service life and greatly reduced number of parts (17 for a disc brake assembly compared to 64 for a drum brake) results in considerable maintenance cost savings. The new brake system also offers improved resistance to fade from both heat and water, and better braking stability.]]></description>
      <pubDate>Fri, 29 Apr 1983 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/188499</guid>
    </item>
    <item>
      <title>MOTOR CARRIER ACCIDENT INVESTIGATION. GROVER TRUCKING COMPANY, IDAHO FALLS, IDAHO. RUNAWAY TRUCK ACCIDENT</title>
      <link>https://trid.trb.org/View/178651</link>
      <description><![CDATA[This is the investigative report of a runaway truck accident which occurred on July 15, 1981 on U.S. 95 in White Bird, Idaho. A southbound truck-tractor flatbed semitrailer, operated by the Grover Trucking Company, ran out of control on a steep downgrade and overturned. The units separated with the trailer rolling down the canyon and the tractor continuing ahead, striking a concrete bridge abutment and ejecting the truck driver. The truck driver was killed and $50,000 property damage was incurred. The probable cause of this accident was determined to be excessive speed and the over application of brakes resulting in brake fade and loss of control. It was also found that the truck driver was inexperienced in the operation of tractor trailers.]]></description>
      <pubDate>Thu, 30 Sep 1982 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/178651</guid>
    </item>
    <item>
      <title>THE TRANSIENT FAILURES AS A FACTOR OF THE BRAKING SYSTEM RELIABILITY</title>
      <link>https://trid.trb.org/View/56092</link>
      <description><![CDATA[In spite of the improved reliability of the present braking systems, achieved by increasing the number of parallel links in the system, there still remains an especially delicate question relative to the reliability of the brakes themselves.  Among other things they are liable to a special sort of failure, so-called transient failures, which affect the reliability a great deal and are very difficult to evaluate precisely.  Transient failures, as a specific sort of failure in braking systems in respect to reliability, are manifested as a considerable temporary loss of braking efficiency.  These failures are not of stable character and after a period of time the braking efficiency is spontaneously regained to approximately the same level as prior to the occurrence of such failures. The possibilities of identifying transient failures in service are very small. This is the reason why the importance of such failures should be stressed even more, since the driver very often is not aware of their occurrence.  Namely, the basic transient failures are: fade, contamination and the vapour lock.  The author suggests that the best way for evaluating the importance of transient failures is the development of laboratory testing methods and the appropriate theoretical analysis of the probability of their occurrence.  In addition to this, the paper explains the mechanism of occurrence of transient failures, it gives the principles of the developed testing methodology which involves a great number of fade and contamination tests, and it offers some basic conclusions associated with the importance of the problem which are obtained from the performed testing. /Author/TRRL/]]></description>
      <pubDate>Wed, 14 Jun 1978 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/56092</guid>
    </item>
    <item>
      <title>INCIDENTS CAUSED BY VEHICLE DEFECTS-ANALYSIS OF THEIR CHARACTERISTICS</title>
      <link>https://trid.trb.org/View/48379</link>
      <description><![CDATA[Data from in-depth investigations of 1,087 incidents caused by vehicle defects reported to an automobile insurer were examined, compiled into various categories and analyzed. Significant results were that 530 (49%) of the incidents involved vehicle fuel system failures which caused fires. Brake system failures accounted for 301 of the remaining 557 incidents.  Conclusions and recommendations are made supportive of countermeasures such as recall campaigns, upgrading of vehicle service facilities and vehicle owner education.  The cost effectiveness of mandatory periodic motor vehicle inspection systems is questioned, further research, generally on vehicle safety defects and specifically on the causes of vehicle engine fires, is recommended. /HSRI/]]></description>
      <pubDate>Tue, 31 May 1977 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/48379</guid>
    </item>
    <item>
      <title>DEVELOPMENT OF POLICE CAR BRAKE STANDARDS</title>
      <link>https://trid.trb.org/View/32760</link>
      <description><![CDATA[In 1957 the Los Angeles Police Department recognized the need for improvement in braking systems on police emergency vehicles.  From that date to the present time, there has been an ongoing program of testing and evaluating brake linings and braking systems to provide fade-free balanced braking.  As a result of this program, substantial improvements have been made in developing brake characteristics which point the way for police vehicle braking standards.  /HSRI/]]></description>
      <pubDate>Tue, 15 Jul 1975 00:00:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/32760</guid>
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