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Heavy vehicle stability and control performance measures are commonly used as an objective tool for the development of heavy vehicle size and weight policy. In some jurisdictions of Canada, the use of performance measures has expanded to help support screening protocols for non-conforming vehicles under special permit systems. Special permit systems allow for the acceptance of vehicles not covered by standard size and weight policy. A given vehicle may be designed for overweight or over dimension applications to improve transport efficiency or to transport indivisible loads usually on specified routes. This paper describes two systems currently in place in Canada and presents a case study to illustrate the technical procedures used.

This paper is an empirical analysis of trucking and truck size and weight (TS&W) regulations and policy issues in the Texas-Mexico border region. Truck size and weight regulations and policy issues that result from those regulations have an effect on the trucking activity, freight movements, highway safety, and the economy of a region. To evaluate policy issues in a region like the U.S.-Mexico border, it is necessary to first of all, understand the trucking activity and freight movements that take place in this area of the country. With this understanding it is possible to draw conclusions regarding TS&W policy, which may assist decision-makers address policy questions from the perspective of this border.

The CLUTCH WEAR ANALYZING TECHNOLOGY has been developed by Mannesmann Sachs to obtain detailed information of the friction load of clutch facings during vehicle operation. A special challenge was the self-imposed task not to install additional sensors. This became possible by using/reading the CAN (Controller Area Network) bus signals.

Carnegie Mellon Driving Research Center, together with ISIM, is presently involved in the design and development of an Advanced Human Factors Research and Driving Training Research Facility. The facility has been designed to address human factors issues and driver training issues. Human factors interests include developing countermeasures for fatigue and driver/vehicle interface issues. Driver training issues include validating the usefulness of simulators for driver training, developing effective curricula and investigating simulator fidelity needed for effective training. A key component of the facility is the Carnegie Mellon TruckSim that will be capable of simulating a variety of commercial and emergency vehicles using interchangeable cabs mounted to a common motion platform. TruckSim's modular configuration will allow for rapid and cost effective design of experiments and training scenarios. A first research program to evaluate fatigue countermeasures is presented as an example.

Leaf springs must be regarded as safety components of a vehicle which failures can cause severe accidents. They have to fulfill various functions as a spring element and for guiding the axles and are also responsible for driving comfort. Therefore, the durability approval must be carried out under representative service-like loading, which take into account complex leaf deformations in operational usage. In this paper the influencing parameters for the durability approval of leaf spring suspensions are discussed and the test rig and the standardized test program SPRILOS (SPRIng LOad Sequence) for the durability approval are described.

The stabilizer bar attachments problem can not be simply analyzed by using linear FEA methodology. The large deformation in the bushing, the elastic-plastic material property in the bushing retainer bracket, and the contact between different parts all add complexity to the problem and result in the need for an analysis method using a non-linear code, such as ABAQUS. The material properties of the bushing were experimentally determined and applied to the CAE model. It was found that using strains to estimate the fatigue life was more accurate and reliable than using stress. Many modeling techniques used in this analysis were able to improve analysis efficiency.

Of the several types of performance-based brake testers (PBBTs), roller dynamometers (RDs) have been used for more than 20 years in Europe to judge the braking capabilities of commercial vehicles and for enforcement of minimum brake performance requirements. These RDs, however, have been exclusively of the in-ground design. In recent years, both in Australia as well as in the United States, the use of portable RDs for assessing commercial vehicle braking performance has been increasing. This paper describes some of the differences between the two types of RDs. Analyses of the effect of the roll geometry and coefficient of friction on maximum brake force measurements are made. It is concluded that careful considerations must be taken with the use of such measurements for predicting stopping distance and braking stability using the results from both in-ground as well as portable RDs. Recommendations are made based on the results of the analyses.

Eleven focus groups were conducted nationwide to gain an understanding, from the local/short haul (L/SH) drivers' perspective, of the general safety concerns related to L/SH trucking and, specifically, the degree to which fatigue plays a role. As part of the discussions, drivers listed and ranked issues that they believed caused them fatigue on the job. The top five fatigue-related issues, ranked in terms of importance, were: (1) Not Enough Sleep, (2) Hard/Physical Workday, (3) Heat/No Air Conditioning, (4) Waiting to Unload, and (5) Irregular Meal Times. Based on the results of these focus groups, it appears that Fatigue is an issue in L/SH, but perhaps not to the extent that it is in long-haul.

To better understand the issues surrounding commercial driver reliance upon in-vehicle sleeper berths for rest, ten focus groups were conducted with long-haul operators. These focus groups were held in eight cities across seven states to provide a geographically diverse sample of long-haul drivers. Issues that were explored included factors affecting the quality and quantity of sleep that drivers receive in sleeper berths, drivers' physical and mental fatigue while on the road, and other related safety issues associated with long-haul truck operations where sleeper berths are used. The results of these focus groups are presented and reflect a wide variety of driver comments, perceptions, suggestions, and recommendations.

The durability approval of truck axles is performed on proving grounds with well defined road characteristics as well as in laboratory test facilities simulating these loading conditions. These proof out tests are supposed to reproduce within a reasonable time the customer usage conditions which are expected during the life of a vehicle taking into account the large scatter of service. The programs and requirements are based on extensive measurements as well as long term experience. However, the development of vehicles for specific mission profiles as well as the introduction of components from new light weight material and innovative manufacturing technologies with different durability properties, requires procedures for the evaluation of the programs themselves. Within this paper the procedure of a comparative damage evaluation of test track and laboratory test programs with respect to an appropriated mission profile is demonstrated as example on a truck axle.

Since 1996 a 2nd Generation EBS has been available in Europe as an advanced brake system offering a variety of advantages to the OEM as well as to the truck and fleet owner. EBS enhances vehicle safety and improves the braking performance to a “passenger car like” braking feel, allowing less experienced drivers better vehicle handling. The brake lining wear control and retarder integration allow the reduction of operational costs. The safety enhancements achieved by EBS in conjunction with disc brakes, are rewarded by European truck insurance companies by lower insurance fees. The importance of EBS will still gain significantly through the developments in process. EBS is the platform for ESP and ACC, which will be a major contributer to better integration of trucks in dense traffic flow.

In the last 15 years bus front axle suspensions have seen important developments and improvements: Public transit authorities, particularly in America, have requested buses offering easy access for mobility-impaired people. To meet this requirement a new front axle technology was demanded, offering a wide space between the wheel arches as well as the well known low floor concept. Regarding front axle systems for coaches, significant improvements have been introduced in Europe and are now making their way into modern North American coach-concepts. The traditional rigid beam front axle will eventually be replaced by independent front axle suspensions, which offer best ride quality and driving behavior of the bus for passengers and drivers. The ZF-group, as one of the world leaders in modern axle system technology for all sorts of vehicles, has provided axle systems for transit buses and coaches for more than 15 years.

Vehicle and traffic safety improvement is one of the most important targets in the vehicle industry. The introduction of ABS for commercial vehicles, meanwhile standard in various countries, was one of the major safety improvements. This system, based on electronics, sensors and actuators shows what is achievable by controlling brakes of such heavy vehicles at the physical limits under various road conditions. With EBS (brake-by-wire) further safety features are integrated including active access of each wheel brake that allows, independent from the driver to apply the brakes to keep the vehicle stable. Electronic stability control as the overall vehicle control system integrated into EBS leads to a new generation of driver assistance concepts. The concept of Electronic Stability Control (ESC) integrated into EBS, simulation studies of vehicle behavior in critical situations, the control strategies and discussion of test results are the main content of this paper.

The need to reduce the injury to pedestrians that are run over or pinned beneath a bus is an ongoing concern for transit authorities and other operators. Occasionally, a pedestrian will be run over by the right rear wheel while exiting the rear door. This accident occurs in various scenarios such as when people exit the bus and become entangled in the door grab bars, or when they fall between the curb and the bus while it approaches or departs. With all scenarios, the S-1 Gard acts similar to a cow catcher, pushing the fallen pedestrian out and away from the rear tire. This paper will: outline various incident scenarios, evaluate the S-1 Gard's performance in a city environment, review installation of the guard as well as its maintenance requirements. The purpose of this paper is to bring to the attention of transit authorities and shuttle operators the overall value of this device.

This paper provides final results of an accident investigation study conducted by the Road Safety Team of École Polytechnique de Montréal, for the Société de l'Assurance Automobile du Québec (SAAQ). Particular emphasis is placed on the role of mechanical condition of trucks and tractor trailers in accident causation. These results are put in context with the evaluation of the impact of the annual Mandatory Mechanical Inspection Program (MMIP) carried out in the province of Québec, by analyzing the nature and frequency of defects. The relation between age and mechanical condition is discussed. Air-brake system efficiency and maintenance is also addressed. Furthermore an indicator of accident-causing potential is defined for each major mechanical component, based on their contribution to the investigated accidents.

The Pennsylvania Transportation Institute (PTI) operates the Bus Testing and Research Center for the Federal Transit Administration (FTA). The objective of this paper is to present a summary of important findings during the first eight years of Center operation. This paper presents an overview of the test procedures and a descriptive matrix of vehicles submitted for testing. A summary of test results is provided, which includes a distribution of failures classified by severity and subsystem type. The paper briefly describes the developmental status of including brake performance and emissions testing as well as future plans for the implementation of electric and hybrid-electric bus testing.

The handling and ride comfort characteristics of a medium bus during a single lane change manoeuvre and bump pass are investigated in terms of the change of the center of gravity, stiffnesses of springs, and damping coefficients through computer simulation using DADS. Dynamic full model of the vehicle is established using tires, dampers, leaf springs, sprung mass, and unsprung masses. A driver is assumed to steer the vehicle along a prescribed path which was obtained from field tests. He was modeled as a PID controller in the simulation. In order to confirm the validity of the model, simulation results are compared with those obtained from field test. The handling and ride comfort characteristics of the vehicle are compared with root mean square values.

As competitive pressures in the automotive industry continue to increase the need for reduction in product development time, OEM's are searching for ways to eliminate non-valued added activities. Today, still too much time is devoted to the laborious process of manipulation of CAD geometry in the advanced stages of a program in order to develop feasibility for emerging design themes, involving the packaging and function of vehicle systems. Technology is being developed that will eliminate much of the tedium currently involved in this design engineering process. As theme iterations or packaging changes occur, CAD models that intelligently link the theme, the packaging, and the engineering “rules” will automatically “morph” into new designs. This Morphing process will execute CAD model changes according to engineering rules that are considered to be industry best practices.

This paper will introduce the concept of Concept and Concurrent Analysis and Optimization (CCAp for short), and discuss its merits and challenges for its successful application, from a technical perspective. Increasingly strong emphasis have been placed upon integrating analysis and optimization into a product design and development process (PD&D for short) for shorter time-to-market, lower cost, and increased quality and reliability. However, its effect and influence are ultimately limited in scope and extent to downstream from its entry into the process. CCAp promotes early introduction (at and before concept) and continued application (concurrent) along design evolution paths in a process. Concepts, which exist at all levels and on all scales throughout an entire process, are when design changes and variations are the easiest and least expensive to make, and when optimizations are the least constrained and the most effective.

The increase in automotive systems complexity coupled with the requirements to meet tight development schedules and costs, have pushed development teams to find new ways of delivering their product on time. Over the past few years, simulation has become a powerful approach for compressing product development cycles. However, systems are defined using components from different engineering domains such as control system design, mechanical design, hydraulic design, circuit design or software design. Each of these components generally requires different simulation tools. Using these tools each development team independently designs and simulates their specific component. While the current simulation approaches are appropriate for component design, system simulations are harder to execute and maintain. This paper presents a new architecture for co-simulation using distributed object referred as CUDOs. An implementation of the architecture is used to provide a cosimulation example.