Actual Road Conditions Research Articles

On-road assessment of in-vehicle driving workload for older drivers: Design guidelines for intelligent vehicles

There has been recent interest in intelligent vehicle technologies, such as advanced driver assistance systems (ADASs) or in-vehicle information systems (IVISs), that offer a significant enhancement of safety and convenience to drivers and passengers. However, the use of ADAS- and IVIS-based information devices may increase driver distraction and workload, which in turn can increase the chance of traffic accidents. The number of traffic accidents involving older drivers that are due to distraction, misjudgment, and delayed detection of danger, all of which are related to the drivers’ declining physical and cognitive capabilities, has increased. Because the death rate in traffic accidents is higher when older drivers are involved, finding ways to reduce the distraction and workload of older drivers is important. This paper generalizes driver information device operations and assesses the workload while driving by means of experiments involving 40 drivers in real cars under actual road conditions. Five driving tasks (manual only, manual primarily, visual only, visual primarily, and visual-manual) and three age groups (younger (20–29 years of age), middle-aged (40–49 years of age), and older (60–69 years of age)) were considered in investigating the effect of age-related workload difference. Data were collected from 40 drivers who drove in a real car under actual road conditions. The experimental results showed that age influences driver workload while performing in-vehicle tasks.

Performance Evaluation of a Crossing-Assistance System for Visually Disabled Persons at Intersections Considering Actual Road Structure

This paper evaluates, through outdoor experiments and a questionnaire, the performance of a crossing-assistance system for visually disabled persons at signalized intersections by utilizing pedestrian traffic signals in concert with visible light communication (VLC) technology. From the results of the survey, it is found that the guidance given by the VLC system enables the visually disabled to cross safely at signalized intersections, under actual road conditions. The applicability of the system is highly evaluated.

New Method to Assess Ride Safety on Uneven Element Pavements

Stone element pavements are typical of many historical urban centers in Europe. Unfortunately, their deterioration due to traffic causes severely uneven road surfaces, compromising the safety of those who ride on two-wheeled vehicles. The writers have developed a method to quantify the danger level in relation to actual road conditions by creating a mechanical model able to simulate two-wheeled vehicles on road discontinuities. Several combinations of road discontinuities and approach speeds were tested in order to determine transit safety. These model discontinuities, varying in kind and magnitude, were examined using both rectilinear trajectories and curves. Specific criteria and related thresholds were set up to identify hazardous situations. This method was used on stone element pavements with embedded tram tracks. The level of danger for each condition was thus evaluated using these criteria. Finally, we listed in a table the thresholds for the acceptable pavement discontinuities in order to formulate suggestions for maintenance management and speed limitations.

Experimental Analysis of Out‐of‐Plane Structural Vibrations of Two‐Wheeled Vehicles

An analysis of the handling and stability of two‐wheeled vehicles depends on structural flexibility. This paper deals with laboratory experimentation carried out to identify the vehicle′s structural modes of vibration. The tests were carried out in stationary conditions considering several combinations of constraints.Although the testing conditions did not correspond completely to actual road conditions, information about the influence of structural modes on weave and wobble modes was obtained. An analysis of the Frequency Response Functions obtained from several kinds of tests made it possible to establish the best testing conditions to obtain the desired information.Experimental results regarding a super‐sport motorcycle and a maxi‐scooter are presented and discussed in this paper.

Instrumented Vehicles and Driving Simulators

Judgments on fitness to drive in older drivers should rely upon empirical observations of performance, because decisions based on age alone may unfairly deny patients their mobility or unwisely authorize licensure in unfit older drivers. Instrumented vehicles permit quantitative assessments of driver performance in the field, under actual road conditions. These measurements are not subject to the type of human bias that affects inter-rater reliability on a standard road test. Moreover, the internal network of modern vehicles makes it possible to obtain information from the driver's own automobile, providing an unprecedented window on driver strategy, vehicle usage, upkeep, drive lengths, route choices, and decision-making. Driving simulators make it possible to observe driver errors with optimal stimulus and response control in an environment that is challenging yet safe for the driver and tester, without the risk of driving on the road. Together, instrumented vehicles and driving simulators can provide a wealth of complementary information relevant to predictive models of driver safety, fair and accurate criteria for driver licensure, and effective injury prevention countermeasures in at-risk older drivers.

Genetic-based fuzzy control for half-car active suspension systems

In this paper, a fuzzy controller is designed for automotive active suspension systems. A half-car model is used in order to consider the pitch angle of the body and the coupling dynamics of front and rear wheels. It is assumed that the three measurements of body acceleration, front suspension deflection and rear suspension deflection are available. The fuzzy control rules are separately designed for each measurement. After the fuzzy control rules are determined, a genetic algorithm is applied to tune the membership functions of these control rules. To measure the performance of the designed genetic-based fuzzy active suspension system, three road disturbance models are designed to simulate actual road conditions. The performance of the designed system is evaluated with respect to these disturbance models, and it is shown that the designed active suspension system provides good performance in improving ride quality and maintaining vehicle maneuvrability. It is also shown that the designed active suspension system shows robust performance with system model uncertainties.

Road Surface Correction o f Tire Test Data

SUMMARY Most tire data used for vehicle simulations is measured on laboratory test facilities. An investigation showed that the frictional properties of these laboratory machines can be quite different from actual road conditions. This paper describes a method to correct laboratory tire test data to be more like road data in order to achieve a higher degree of correlation between instrumented test- and simulation results.

The poor man's five-mode whole-body shaker

The Institute is concerned (among other things) with the effects of whole-body vibration on the musculo-skeletal system as well as effects to psycho-motor performance on the operators of heavy vehicles. To study these effects in the laboratory setting requires a simulation of the actual road or field vibration conditions, i.e., three axes of translation and two of rotation. This paper describes the theory, design, and construction of a simple, relatively inexpensive shaker system driven by a single hydraulic cylinder. This system can produce all five modes simultaneously with a minimum of 0.4 g at 1 Hz. Frequency response is 1–30 Hz.

Paper 7: Corrosion in the Motor Vehicle Braking System

The paper introduces the subject of corrosion in brake systems, showing possible reasons for its emergence as a major problem, and the various types of corrosion are noted. The causes and effects of corrosion, and the deterioration of brake performance which may result, are described. Methods of protection and prevention are discussed and the importance of past experience in the development of new products is stressed. It notes that accelerated test methods are essential to simulate as closely as possible actual road conditions. The paper concludes by reviewing new materials and their possible application.

COMPARISON OF AUTO EXHAUST EMISSIONS IN TWO MAJOR CITIES.

Exhaust emissions from automobiles in a low-altitude city will be compared with emissions from autos in a high-altitude city (Denver, Colorado). The comparison will be based on samples collected from thirty five cars driven under actual road conditions in each city. Results will be discussed on the basis of CO, CO2 and hydrocarbon concentrations versus average route speeds and on pounds of CO, CO2 and hydrocarbons, emitted per mile, versus average route speed.