Biomedical subjects

P P Jovanis

Publications and source records attributed to P P Jovanis.

5 recordsLinked to original sources

PubMed1997

Effect of selected in-vehicle route guidance systems on driver reaction times.

Experiments were conducted in a fixed-base, high-fidelity simulator to evaluate selected in-vehicle route guidance systems. Drivers navigated a simulated network using five route guidance systems: paper map, head-down turn-by-turn display, head-down electronic route map, head-up turn-by-turn display, and an audio guidance system. The primary measure of driving performance was the reaction time to a scanning task. Other measures included navigation errors, workload, and perception ratings. Censored regression models were developed to study the effect of route guidance type on reaction times. Results indicated that the drivers responded the fastest while using the audio system and the slowest while using the paper map. The head-up turn-by-turn display was associated with lower reaction times compared with an identically designed head-down turn-by-turn display. The head-down electronic map, despite its complexity, performed better than the head-down turn-by-turn display.

Adult↗

PubMed1992

Multiday driving patterns and motor carrier accident risk: a disaggregate analysis.

A method has been developed to estimate the relative accident risk posed by different patterns of driving over a multiday period. The procedure explicitly considers whether a driver is on duty or off duty for each half hour of each day during the period of analysis. From a data set of over 1,000 drivers, nine distinct driving patterns are identified. Membership in the patterns is determined exclusively by the pattern of duty hours for seven consecutive days; for some drivers an accident occurred on the eighth day while others had no accident, therefore each pattern can be associated with a relative accident risk. Additional statistical modeling allowed the consideration, in addition to driving pattern, of driver age, experience with the firm, hours off duty prior to the last trip and hours driving on the last trip (either until the accident or successful completion of the trip). The finding of the modeling is that driving patterns over the previous seven days significantly affect accident risk on the eighth day. In general, driving during the early and late morning (e.g., midnight to 10 A.M.) has the highest accident risk while all seven other multiday patterns had indistinguishable risk. Consecutive hours driven also has a significant effect on accident risk: the first hour through the fourth hour having the lowest risk with a fluctuating increase in risk to a maximum beyond nine hours. Driver age and hours off duty immediately prior to a trip do not appear to affect accident risk significantly. These findings quantitatively assess the relative accident risk of multiday driving patterns using data from actual truck operations. Further research is recommended in the areas of refining model structures, adding explanatory variables (such as highway type), and testing more complex models.

Accidents, Occupational↗

PubMed1990

Formulating accident occurrence as a survival process.

A conceptual framework for accident occurrence is developed based on the principle of the driver as an information processor. The framework underlies the development of a modeling approach that is consistent with the definition of exposure to risk as a repeated trial. Survival theory is proposed as a statistical technique that is consistent with the conceptual structure and allows the exploration of a wide range of factors that contribute to highway operating risk. This survival model of accident occurrence is developed at a disaggregate level, allowing safety researchers to broaden the scope of studies which may be limited by the use of traditional aggregate approaches. An application of the approach to motor carrier safety is discussed as are potential applications to a variety of transportation industries. Lastly, a typology of highway safety research methodologies is developed to compare the properties of four safety methodologies: laboratory experiments, on-the-road studies, multidisciplinary accident investigations, and correlational studies. The survival theory formulation has a mathematical structure that is compatible with each safety methodology, so it may facilitate the integration of findings across methodologies.

Accidents, Traffic↗

PubMed1989

Disaggregate model of highway accident occurrence using survival theory.

The analysis of discrete accident data and aggregate exposure data frequently necessitates compromises that can obscure the relationship between accident occurrence and potential causal risk components. One way to overcome these difficulties is to develop a model of accident occurrence that includes accident and exposure data at a mathematically consistent disaggregate level. This paper describes the conceptual and mathematical development of such a model using principals of survival theory. The model predicts the probability of being involved in an accident at time t given that a vehicle has survived until that time. Several alternative functional forms are discussed including additive, proportional hazards and accelerated failure time models. Model estimation is discussed for the case in which both accident and nonaccident trips are included and for the case with only accident data. As formulated, the model has the distinct advantage of being able to consider accident and exposure data at a disaggregate level in an entirely consistent analytic framework. A conditional accident analysis is undertaken using truck accident data obtained from a major national carrier in the United States. Model results are interpretable and generally reasonable. Of particular interest is that segmenting accidents in several categories yields very different sets of significant parameters. Driver service hours seemed to most strongly effect accident risk: regularly scheduled drivers who take frequent trips are likely to have a reduced risk of an accident, particularly if they have a longer (greater than eight) number of hours off-duty just prior to a trip.

Accidents, Traffic↗

PubMed1986

Childhood pedestrian injury: a pilot study concerning etiology.

For U.S. children of preschool and school age, fatal pedestrian injury is more common than fatal passenger injury, but there is no agreement on preventive approaches and their efficacy. Development of preventive measures requires understanding of how and why such injuries occur, which in turn requires better methods to sort out the many factors which appear to contribute to the problem. In an attempt to develop the broadest possible picture of the dynamics of child pedestrian injury, a multidisciplinary process was developed to collect and interpret medical, traffic, social, psychological and behavioral information concerning specific injury events. In a pilot study, the process was used to study six pedestrian injuries. The pilot study indicated that: the multidisciplinary approach identified possible etiologic factors missed without it; this approach requires the availability of high quality medical information and police accident records; biological, psychological, and social characteristics of victims, victim families and communities appear to affect the occurrence of child pedestrian injuries; and, such victim factors must be considered in development of countermeasures. It is concluded that the technique of multidisciplinary analysis merits further application as a productive way to generate quantitatively testable hypotheses concerning childhood pedestrian injury causality and potential countermeasures.

Accident Proneness↗