Alarm mistrust in automobiles: how collision alarm reliability affects driving

The safe operation of vehicles on roads depends, among other things, on a properly functioning brake system. Air brake systems are widely used in commercial vehicles such as trucks, tractor-trailers, and buses. In these brake systems, compressed air is used as the energy transmitting medium to actuate the foundation brakes mounted on the axles. In this paper, a model-based diagnostic system for air brakes is presented. This diagnostic system is based on a nonlinear model for predicting the pressure transients in the brake chamber that correlates the brake chamber pressure to the treadle valve (brake application valve) plunger displacement and the pressure of the air supplied to the brake system. Leaks and "out-of-adjustment" of push rods are two prominent defects that affect the performance of the air brake system. Diagnostic schemes that will monitor the brake system for these defects will be presented and corroborated with experimental data obtained from the brake testing facility

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A Diagnostic System for Air Brakes in Commercial Vehicles

The sustainable development of vehicle propulsion systems that have mainly focused on reduction of fuel consumption (ie CO2 emission) has led, not only to the development of systems connected with combustion processes but also to legislation and testing procedures In recent years, the low carbon policy has made hybrid vehicles and fully electric vehicles (H/EVs) popular The main virtue of these propulsion systems is their ability to restore some of the expended energy from kinetic movement, eg the braking process Consequently new research and testing methods for H/EVs are currently being developed This especially concerns the critical ‘use-cases’ for functionality tests within dynamic events for both virtual simulations, as well as real-time road tests The use-case for conventional vehicles for numerical simulations and road tests are well established However, the wide variety of tests and their great number (close to a thousand) creates a need for selection, in the first place, and the creation

Regenerative braking strategies, vehicle safety and stability control systems: critical use-case proposals

Classification of driver-assistance systems according to their impact on road safety and traffic efficiency

In recent studies, it has become apparent that a set of safety–related performance measures for heavy vehicles can be useful in the design process as well as in the more conventional realm of screening heavy vehicles by regulation. In Canada, these regulations control, separately, the combined trailer length and overall vehicle length, total vehicle weight, maximum axle–load, multiple–axle group spacing, and the characteristics of a few selected components of new vehicles (e.g. service and emergency air and/or hydraulic brake systems). None of the existing regulations has been applied for quantifying the dynamic properties of individual vehicles, either newly designed or already in service; instead they have been used to qualify classes or groupings of vehicles. The objective of this paper is to present an overview of the efforts made in North America to develop a set of safety–related performance measures and promote their use for determining and controlling the dynamic quality of heavy vehicles on an individual basis from both the design and regulatory standpoints.

An overview of performance measures for heavy commercial vehicles in north america.

Tractor and Trailer Brake System Compatibility

To determine if situations and/or conditions exist in which ABS-equipped vehicles do not perform as well as those without ABS, the braking performance of nine passenger vehicles was observed over a comprehensive array of driving conditions. For most maneuvers, on most surfaces, ABS-assisted stops yielded distances shorter than those made with the ABS disabled. The one exception was on loose gravel where stopping distances increased by an average of 27.2 percent overall. Additionally, the vehicular stability observed during testing was almost always superior with ABS. For the cases in which instability was observed, ABS was not deemed responsible for its occurrence.

A Comprehensive Light Vehicle Antilock Brake System Test Track Performance Evaluation

This paper focuses on two types of electronics-based object detection systems for heavy truck applications: those sensing the presence of objects to the rear of the vehicle, and those sensing the presence of objects on the right side of the vehicle

Hardware evaluation of heavy truck side and rear object detection systems

Numerous crash data statistical analyses conducted over the past few years suggest that, for automobiles, the introduction of four-wheel antilock brake systems (ABS) has produced net safety benefits much lower than originally expected. The studies indicate the apparent increase in single-vehicle crashes involving passenger cars equipped with four-wheel ABS almost completely offsets the safety advantage such vehicles have over their conventionally-braked counterparts. The braking performance of nine high production passenger vehicles was evaluated in eighteen stopping situations. These situations were comprised of various road surfaces, driver steering actions, and vehicle speeds. Testing was performed with lightly and heavily laden vehicles, with the ABS active and disabled, and used two brake pedal application techniques. The selected vehicles included at least one ABS from each of the eight current, major, ABS manufacturers. This study found that for most stopping maneuvers on most surfaces, ABS-assisted full pedal brake application stops were shorter than those made with the ABS disabled. The one systematic exception was on loose gravel where stopping distances increased by an average of 27.2% overall. Additionally, the vehicular stability during testing was almost always superior with the assistance of ABS. For the cases in which instability was observed, ABS was not deemed responsible for its occurrence. Based on results to date, the authors of this study believe ABS braking performance deficiencies are not responsible for the apparent increase in ABS-equipped, single-vehicle, run-off-the-road crashes.

Nhtsa light vehicle antilock brake system research program task 4: a test track study of light vehicle abs performance over a broad range of surfaces and maneuvers

This paper presents an assessment of the driver interface component of side collision avoidance systems. It looks at the design of the interfaces, and recommendations are presented regarding ergonomically desirable or undesirable features. A preliminary set of driver interface performance specifications are listed.

Mark A. Flick

Papers

Tractor and Trailer Brake System Compatibility

A Comprehensive Light Vehicle Antilock Brake System Test Track Performance Evaluation

Hardware evaluation of heavy truck side and rear object detection systems

Nhtsa light vehicle antilock brake system research program task 4: a test track study of light vehicle abs performance over a broad range of surfaces and maneuvers

Human factors evaluation of existing side collision avoidance system driver interfaces