This appendix describes data sources, papers, reports, and books that were consulted during this study but not discussed directly in the Section 2, Literature Review. Although the annotated references were not used directly for the report preparation, they served to provide background material and information or to validate another source and indicate its applicability to the project. Material here is organized under the following categories used for the Literature Review in Section 2.

Data and studies on crashes and OOS violations that could be prevented or mitigated,
The need for better driver/ brake technician training and inspection,
Existing brake training programs, and
Economic analysis techniques.

No additional annotated references are described under economic analysis techniques.

B.1 Data and Studies for Use in Estimating Crashes and OOS Violations That Could be Prevented or Mitigated

(CPIR-B File) Smist, T.E.;Ramney, T.A., Heavy Truck Causation: Analysis of the CPIR-B File; U.S. Department of Commerce, National Technical Information Service, April 1983

The CPIR-B (Heavy Truck) accident file identifies specific factors related to heavy truck accident causation. The population of over 335 trucks includes both straight and articulated (semis) trucks but was selected by a number of different sources over a number of years. Consequently, the sample is not random or necessarily representative of the overall population of large trucks. Furthermore, the methodology concerning how the various accident categories were determined is not fully detailed. This makes it difficult for the reader to evaluate the usefulness of the data.

The analysis does provide a tabulation of component failures for those vehicles involved in the crashes. For the 335 trucks involved in the accidents, known brake failure represents 3.6 percent of the total.

(FACT Database) Shelton, Terry, 'What is the Current Level of Compliance?" North American Brake Safety Conference, Toronto, Canada, September 2000

The contribution of brake defects as a contributor to truck crashes is uncertain. Some study analyses show brake defects being responsible for up to 45 percent of truck crashes and trucks involved in crashes are at least as likely to have brake defects as trucks sampled randomly. The Michigan FACT project, which included a detailed field inspection of trucks involved in fatal accidents, showed that about 31 percent of trucks involved in fatal crashes had brake defects. However, it is uncertain how often these defects actually caused the crash.

Fleischer, G.A., Philipson L.L., Statistical Analysis of Commercial Vehicle Accident Factors Volume II - Summary Report. NHTSA, Washington D.C, 1978

This report is based on an analysis of about 3,000 California State Highway Patrol accident reports for a one-year period. The statistical analysis focuses on quantitative risk analysis. The report does include a breakdown of the "inadequacy of certain functions." Braking in-lane represented 27 percent, brake and steering 15.8 percent, brake-fade 0.7 percent, brake-caused 3.3 percent for skid, and 3.3 percent for leaving lane. However, in only about 200 cases did an officer cite equipment violations.

Freund, Deborah M., Woodford, Gary R., Minor, Larry, "Stopping on 18 Dimes: A Decade of Progress in Motor Vehicle Brake Safety." Proceedings of 2002 International Large Truck and Bus Safety Research and Policy Symposium, Knoxville, TN, 2002.

This article describes the changes in brake safety standards over time, the role of the FMCSA in brake safety and publishing brake regulations, and the trend in OOS brake violations identified in inspections from fiscal years 1989 through 2000. The article cites the development and adoption of automatic brake adjusters and brake adjustment indicators as being major steps forward in ensuring brake safety. Both NHTSA and FMCSA have been active in issuing rules requiring anti-lock braking systems (ABSs).

Performance-based brake testing has been supported by the FMCSA, which has published specifications for brake-testing machines purchased by States with FMCSA grants. The FMCSA also proposed regulations for pass/fail criteria to be applied to brake testers that are used in CMV inspections.

The article also examines data from roadside inspections concerning the number of OOS brake violations found during each of the fiscal years from 1989 through 2000. The data show a decrease in OOS brake conditions from 54.6 percent in 1989 to 34.3 percent in 2000. The authors attribute the improvement in reducing the number of OOS brake adjustment violations by more than 60 percent.

It may be possible to determine the reduction in crashes over the same time period and estimate the fraction of those that may be attributed to the reduction in OOS brake adjustment violations

Jones, Ian S., Stein, Howard S., Vehicle and Driver Factors in Relation to Crash Involvement of Heavy Trucks. (Insurance Institute for Highway Safety) Proceedings of Strategic Research Program and Traffic Safety on Two Continents in Gothenburg, Sweden, September, 1989. VTIrapport 351A, 1990.

Large truck (greater than 10,000 pounds) crashes on Washington interstates were investigated for a two-year period. For each large truck involved in a crash, three trucks were randomly selected for inspection at the same location and time of day as the crash but one week later. The effects of truck and driver characteristics on crashes were assessed by comparing their relative frequency among those trucks that crashed compared to the sampled trucks. The study found that trucks with defective equipment were over-involved in crashes. Trucks with brake defects had a crash risk one-and-a-half times that for trucks without brake defects.

The study involved 667 crashes involving 734 large trucks over a two-year period. The sample was then limited to tractor trailers. These represented about 60 percent of the crash sample. Seventy-seven percent of crashes involved tractor trailers had at least one defect violation compared to 66 percent of the comparison sample. Trucks with brake defects were present in 56 percent of the crash sample compared with 44 percent of the comparison sample. Thus, the relative risk for trucks with out-of-service defects (OOS) was estimated to be 1.7. Trucks with only violation defects (and not placed OOS) were 1.5 times the risk. Clearly, defective brakes on tractor trailers result in more accidents than trucks with good brakes. However, the actual increased risk for a crash must also take into account such factors as driving long hours and driver inexperience.

Kolstad, James and Harris, Claude, Air Brake Problems-New NTSB Recommendations (Sessions Summary), The Trailblazer, October 1992.

This article summarizes a conference session held in October, 1992. The participants agreed that significant brake problems are quite widespread. For example, in 1988, the NTSB investigated 189 heavy truck accidents and found significant braking problems in 32 of them according to Kolstad, a former NTSB chairman (16.9 percent). A 17-month study that began in 1989 examined the brakes on 1,520 5-axle trucks at weigh stations. More than 56 percent of the trucks (856 trucks) were taken out of service because of brake system violations. More than 46 percent of the trucks were placed out of service for OOA brake violations alone.

Kolstad commented on the significance of OOA or deficient brakes by stating that although these brakes can stop or slow a truck in a routine stop, they may be incapable of stopping a truck in an emergency braking operation.

(Operation Air Brake) Ford, David W., Brake Safety on Trucks Still a Concern; MSP Obtains Infrared Cameras, Michigan State Police Online Newsletter, Michigan.gov/msp, September 2002.

The Michigan State Police completed their annual Operation Air Brake report for 2002. The results showed that approximately 15 percent of all trucks checked during the random inspections were placed out of service for brake violations. In 2001, 16 percent of all trucks checked were placed out of service because of brake violations. This percentage of OOS brake violations can be related to crashes that could potentially be avoided with improved inspection and maintenance.

Rune, and Vaa, Truls, The Handbook of Road Safety Measures, Elsevier, Oxford, U.K., 2004.

This handbook summarizes the results of more than 1,700 road safety evaluation studies. The book includes all vehicle types and diverse studies relating to road safety measures. Subjects covered include highway engineering, traffic control, vehicle design, and driver training. Unfortunately, the section on heavy truck ABS and Disc Brakes does not include any studies that focus on heavy truck performance or, more specifically, the role of brake malfunctions in accidents. However, in another section on safety equipment on trucks and heavy vehicles, the authors state that trucks with technical defects have an accident rate that is 70 percent higher than trucks without defects. This indicates that increased inspections of semitrailer trucks should be able to reduce accidents. In a section dedicated to vehicle and garage inspections (including roadside inspections) the authors cite two studies that examine the affect of periodic inspections on heavy vehicles. These are described elsewhere in this literature review.

SafeStat 2003 Data for Preventable OOS as a Percentage of Total OOS Violations, Interpreted by Zonar Systems Corporation, 2003.

Zonar Systems prepared a graph showing the percentage of preventable OOS as a percentage of total violations. Brake violations are shown as 22.14 percent of the total.

Wilson, D.F.; Kenik, E.A.; Blau, P.J., Evaluation of Corrosion Failure in Tractor-Trailer Brake System. Oak Ridge National Lab., TN, July 2002.

This report analyzes an example of a tractor-trailer brake that failed due to corrosion. Although the report indicates that an increasingly large number of brakes on tractor trailers are failing because of corrosion, there is no attempt in the report to quantify this conclusion or to link the number of corrosion induced brake failures to crashes.

B.2 Need for Better Driver/Brake Technician Training and Inspection

Clark, B., Preventive Maintenance: The Key to Dependability, Owner Operator, Vol. 10 Issue No. 4, 1980.

Preventive maintenance for trucks is described as the best way to avoid breakdowns on the road. Preventive maintenance is defined as a series of scheduled inspections and services scheduled on a time or mileage frequency. The purpose is to prevent major problems by catching problems when they are small and by ensuring that parts are properly lubricated. Brake-lining checks are cited as an example of a type of preventive maintenance that keeps watch on lining wear and replaces it before damage is done to the drums. Model preventive maintenance/inspection forms are included with the article.

Technology & Maintenance Council's (TMC) Future Chassis (Brakes) Task Force Future Brake Position Paper (2001)-1, TMC/ATA, Future Truck Program Position Paper, Future Braking System, Equipment User Expectations, 2001.

This paper, which is the result of an effort by a TMC task force, describes future braking systems. The position paper describes the needs of motor carriers with respect to future braking systems during the next 5 to 10 years. The paper notes that the trucking industry has expressed the need for further enhancements resulting in improved product performance, maintenance, and safety. Any improvements made should be compatible with, and not adversely affect, other systems. Future braking systems should significantly reduce stopping distance which would likely reduce the number and frequency of crashes. This will result in a safer vehicle under all driving conditions. In addition, future vehicle changes, such as changes in GVW, vehicle geometry, and vehicle performance improvements, have to be considered in order to satisfy future requirements for stopping distance reduction. The paper recommends that future brake systems have enhanced diagnostics and warning capabilities including status indication for wearable components that require periodic maintenance. Furthermore, the onboard diagnostic capabilities should include maintenance scheduling and service prediction, prior to experiencing severe, unsafe vehicle conditions that would lead to out-of service or worse conditions.

Selected NTSB Reports

The NTSB crash investigations cited below represent those that are brake related. NTSB reports were consulted to gain an understanding of the types of crashes likely caused by pre-crash brake problems.

Highway Accident Report, Collision Between Truck-Tractor Semi Trailer and School Bus Near Mountainburg, Arkansas on May 31, 2001, NTSB/HAR-02/03 PB2002-916203 National Transportation Safety Board, 2002.

This report analyzes a fatal crash that occurred on May 31, 2001, near Mountainburg, Arkansas, involving a Gayle Stuart Trucking, Inc., truck-tractor semitrailer that collided with a 65-passenger school bus operated by the Mountainburg, Arkansas, Public Schools. Three school bus passengers were killed; two other passengers received serious injuries. The southbound truck-tractor semitrailer exited Interstate 540 at State Highway 282 near Mountainburg, Arkansas. The driver was unable to stop at the stop sign at the bottom of the ramp. The 79,040-pound combination unit was traveling approximately 48 mph when it entered the intersection and collided with the right side of the westbound school bus. After their investigation, the NTSB determined that the probable cause of the accident was the truck driver's inability to stop the tractor semi trailer at the stop sign at the bottom of the ramp due to the reduced braking efficiency of the truck's brakes. Furthermore, the NTSB determined that the brakes had been poorly maintained and inadequately inspected.

NTSB/HAB-01/01, Accident No.: HWY-99-FH012, March 2, 1999.

This NTSB report describes a fatal bus crash that the NTSB concluded was caused by malfunctioning brakes. An inspection determined that the steering-axle brakes were OOA and the brake drums had dark spots, typically seen on overheated drums. The drive axle brakes were also OOA to the extent that they were incapable of providing any braking force. The brakes on the auxiliary weight-bearing axle, commonly referred to as a "tag axle," were not operational because they were "cammed over." Both tag axle drums were worn beyond the manufacturer's accepted limits.

On March 2, 1999, a 1979 Motor Coach Industries MC-9, 47-passenger charter motor coach, owned and operated by Shuttle Jack, Inc., (Shuttle Jack) of Santa Fe, New Mexico, carrying 2 adults and 34 children was returning from a ski trip. The bus was descending a 14-mile mountainous roadway when about halfway down the roadway, the driver discovered that the vehicle's air brakes were no longer capable of slowing or stopping the bus. He noted that the brake air-pressure-gauge reading was between 90 and 120 pounds per square inch, which was the normal system operating pressure for this vehicle. During the next 3.5 miles, the driver made several unsuccessful attempts to bring the bus under control by pumping the air brakes, down-shifting the automatic transmission, pulling on the emergency/parking brake valve, and shutting off the engine. Eventually, the driver lost control of the bus while rounding a left-hand curve. The bus departed the right side of the roadway, crashed into a rock embankment, and then rolled onto its left side back onto the roadway. Two passengers were fatally injured and the 35 other occupants received varying degrees of injuries.

NTSB/HAB-02/14, Accident No.: HWY-98-SH-018, February 17, 1998, 4:00 p.m.

This NTSB report describes the fatal crash involving a double semitrailer and a van. The NTSB determined that the likely cause of the accident was inoperable brakes. The driver of the tractor-double semi trailer stated that she noticed traffic on Interstate Highway 405 slowing in front of her and began applying the brakes. When she applied her brakes, the air pressure for the brake system depleted rapidly. The double semitrailer crashed into the first vehicle stopped in traffic ahead, a Dodge van, and pushed it into five other vehicles. The double semitrailer and van erupted in fire. Three van occupants were fatally injured; seven others involved in the collision sustained minor injuries.

B.3 Training Programs

Ohio Commercial Drivers License Manual; Version 2.0, June 1998

The manual provides driver licensing testing information for all drivers who wish to have a CDL. The manual includes pre-trip inspection information for air brakes as well as a section describing how to use the brakes while driving in such situations as on a downhill stretch. This recent commercial driver's handbook was used as a resource for considering driver training measures for brake inspection and maintenance.