Detecting the Deceleration of a Lead Car during Active Control of Virtual Self Motion

2007 ◽  
Vol 51 (24) ◽  
pp. 1522-1525 ◽  
Author(s):  
Anand Tharanathan ◽  
Patricia R. DeLucia
Keyword(s):  
Collision Avoidance ◽  
Active Control ◽  
Traffic Accidents ◽  
Warning Systems ◽  
Mean Response Time ◽  
Traffic Conditions ◽  
Deceleration Rate ◽  
Virtual Self ◽  
Passive Viewing ◽  
Self Motion

Twenty-five percent of traffic accidents involve rear-end collisions. One important factor that may contribute to such collisions is a driver's ability to detect the deceleration of a lead car. Prior studies of deceleration judgments involved passive viewing rather than active control of self motion. The primary purpose of this study was to measure effects of headway and deceleration rate on the detection of deceleration during (simulated) active control. We investigated whether the pattern of such effects was similar to those we reported previously for passive viewing. Consistent with our previous study, the current results indicated that, during active control, mean response time to detect deceleration was longer when headway was relatively far or when deceleration rate was relatively slow. The implication is that collision-avoidance warning systems may have to utilize different criteria for providing warnings under different traffic conditions.

Effects of Optical Flow and Discrete Warnings on Deceleration Detection during Car Following

2005 ◽  
Vol 49 (17) ◽  
pp. 1673-1676 ◽  
Author(s):  
Patricia R. DeLucia ◽  
Anand Tharanathan
Keyword(s):  
Optical Flow ◽  
Collision Avoidance ◽  
Critical Value ◽  
Optical Parameters ◽  
Warning Systems ◽  
Time To Contact ◽  
Future Studies ◽  
Car Following ◽  
Deceleration Rate ◽  
Flow Information

Tau specifies time-to-contact between a driver and a lead car, and is potentially useful to prevent rear-end collisions. However, studies suggest that time-to-contact judgments are based on multiple information sources and that effective information varies with distance. We focused on three questions: Does a driver's response to a lead car's deceleration occur when the car's optical size, expansion rate, or tau reaches a “critical” value? Does effective information differ for near and far lead cars? Is a driver's response affected by discrete warnings (brake lights and auditory warnings) that occur independently of optical flow information? Results suggested that responses were not based on a critical value of the optical parameters considered here, and were affected by discrete warnings. Further, effective information varied with the distance and deceleration rate of the lead car. Results were consistent with prior proposals that advanced brake warning systems and collision-avoidance warning systems can reduce the incidence of rear-end collisions. Future studies of this kind will help to improve the design of collision-avoidance systems and to reduce rear-end collisions.

scholarly journals PEDESTRIAN TRAFFIC CONDITIONS OF RURAL ROADS AND BUILT-UP AREAS: THE ANALYSIS OF THE EXISTING SITUATION AND POSSIBILITIES OF IMPROVING TRAFFIC CONDITIONS

2010 ◽  
Vol 2 (3) ◽  
pp. 60-66
Author(s):  
Nemunas Abukauskas ◽  
Egidijus Skrodenis
Keyword(s):  
Traffic Safety ◽  
Road Safety ◽  
Traffic Accidents ◽  
Road Traffic ◽  
Rural Roads ◽  
Traffic Conditions ◽  
Foreign Countries ◽  
Pedestrian Traffic ◽  
Main Activity

The results of lengthy thorough investigations into traffic safety situation show that the percentage of pedestrians getting involved in road traffic accidents on Lithuanian roads is significantly higher (more than 33 % of the total number of injury and fatal accidents) than that compared to the other European Union member-states. The article studies traffic safety problems and their factors causing the largest influence on the occurrence of these accidents. Considering valuable experience gained by foreign countries, investigation was carried out to establish general and main factors causing insufficient road safety conditions and significance of these factors to road safety. The article also shows the main activity improving road safety in Lithuania and discusses the effectiveness of strategic and local (temporary and long term) measures to improve conditions for pedestrian road safety.

scholarly journals Analysis of Children’s Traffic Behaviour at Signalized Crosswalks as a Precondition for Safe Children Routes Design: A Case Study from Croatia

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Irena Ištoka Otković ◽  
Aleksandra Deluka-Tibljaš ◽  
Sanja Šurdonja
Keyword(s):  
Traffic Safety ◽  
Traffic Accidents ◽  
Daily Basis ◽  
Children And Adolescent ◽  
Traffic Conditions ◽  
Road Users ◽  
Design Speed ◽  
Pedestrian Infrastructure ◽  
The Impact

Children pedestrians represent road users with some specifics because of which it is important to study and take into account their traffic behaviour when traffic infrastructure is designed. Design should ensure and enhance their traffic safety because for decades, traffic accidents have been among the first few causes of children and adolescent mortality. Pedestrian speed is one of the important inputs when pedestrian infrastructure, especially crosswalks, is designed. On corridors where children are expected on a daily basis as independent pedestrians, the infrastructure should be adjusted to their characteristics and needs. The results of a study conducted in two Croatian cities of a similar size but of different urban and traffic conditions are presented in this paper. This study aimed at establishing and analysing children’s pedestrian speed while crossing the signalized crosswalk in the buffer area of elementary schools, mostly on primary roads in the school vicinity. Children aged 5–15 were observed, and accordingly V15, V50, and V85 speeds were established on the basis of altogether 600 measurements. Speed was established for children walking individually, in a group and supervised by adults, and of a different age, and based on their gender, the impact of infrastructural elements on their speed in traffic was also analysed. Significant differences were found between children’s speed measured in similar conditions in analysed cities and between some of the analysed groups. This fact proves that when improving conditions for children’s independent movement, it is important to consider their specifics in order to ensure safe design adjusted to children’s needs and limitations. As design speed in this paper, 15 percentile speed (V15) is considered. Suggestions on how to establish children pedestrian speed for design of routes regularly used by school children are proposed as well as some inputs elicited from the study done in Croatia are presented.

scholarly journals Estimating the Safety Effects of Congestion Warning Systems using Carriageway Aggregate Data

2020 ◽  
Vol 2674 (11) ◽  
pp. 278-288 ◽  
Author(s):  
Hans van Lint ◽  
Tin Thien Nguyen ◽  
Panchamy Krishnakumari ◽  
Simeon. C. Calvert ◽  
Henk Schuurman ◽  
...  
Keyword(s):  
Traffic Safety ◽  
Large Scale ◽  
Warning Systems ◽  
Traffic Conditions ◽  
Average Maximum ◽  
Demand Patterns ◽  
Relative Comparisons ◽  
Large Speed ◽  
Rule Out ◽  
Maximum Deceleration

Is it possible to use just aggregate carriageway data for the evaluation of congestion warning systems (CWS) in large networks—or any system affecting traffic safety for that matter? In this paper, two hypotheses related to this question are tested. The first hypothesis is that it can be done by comparing large-scale congestion patterns on road stretches with and without CWS. The underlying rationale is that heterogeneous congestion patterns with many disturbances, frequent wide moving jams, and large speed differences result in more potentially unsafe traffic conditions than more homogeneous congestion patterns. The second hypothesis is that it is possible to compare differences in average (maximum) deceleration distributions into congestion waves between road stretches with and without CWS. Both hypotheses have been tested for similar bottlenecks with similar demand patterns and the results suggest the first hypothesis must be rejected. Although the idea seems plausible (CWS result in more homogeneous congestion patterns) there were too many confounding factors in the data to make the case. However, persuasive evidence was found for the second hypothesis. Statistically significant differences were found between (maximum) deceleration distributions on road stretches with and without CWS that suggest CWS do—as expected—contribute positively to traffic safety. It thus seems to be possible to monitor safety effects using just average speeds. However, the method is limited to providing relative comparisons. Furthermore, to fully rule out the effects of unobserved factors, more evidence and validation with microscopic data are needed.

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