Recent developments and research needs in modeling lane changing

This paper comprehensively reviews recent developments in modeling lane-changing behavior. The major lane changing models in the literature are categorized into two groups: models that aim to capture the lane changing decision-making process, and models that aim to quantify the impact of lane changing behavior on surrounding vehicles. The methodologies and important features (including their limitations) of representative models in each category are outlined and discussed. Future research needs are determined.

Microscopic cooperative traffic based on NGSIM data

The deployment of new emerging technologies, such as cooperative systems, allows the traffic community to foresee relevant improvements in terms of traffic safety and efficiency. Vehicles are able to communicate on the local traffic state in real time, which could result in an automatic and therefore better reaction to the mechanism of traffic jam formation. An upstream single hop radio broadcast network can improve the perception of each cooperative driver within radio range and hence the traffic stability. The impact of a cooperative law on traffic congestion appearance is investigated, analytically and through simulation. Ngsim field data is used to calibrate the Optimal Velocity with Relative Velocity (OVRV) car following model and the MOBIL lane-changing model is implemented. Assuming that congestion can be triggered either by a perturbation in the instability domain or by a critical lane changing behavior, the calibrated car following behavior is used to assess the impact of a microscopic cooperative law on abnormal lane changing behavior. The cooperative law helps reduce and delay traffic congestion as it increases traffic flow stability.

The effects of lane-changing on the immediate follower : anticipation, relaxation, and change in driver characteristics

This paper investigates the effects of lane-changing in driver behavior by measuring (i) the induced transient behavior and (ii) the change in driver characteristics, i.e., changes in driver response time and minimum spacing. We find that the transition largely consists of a pre-insertion transition and a relaxation process. These two processes are different but can be reasonably captured with a single model. The findings also suggest that lane-changing induces a regressive effect on driver characteristics: a timid driver (characterized by larger response time and minimum spacing) tends to become less timid and an aggressive driver less aggressive. We offer an extension to Newell’s car-following model to describe this regressive effect and verify it using vehicle trajectory data.

A C-ITS based lane-changing advisory for weaving sections

Weaving sections, a common design of motorways, require extensive lane-change manoeuvres. Numerous studies have found that drivers tend to make their lane changes as soon as they enter the weaving section, as the traffic volume increases. Congestion builds up as a result of this high lane-changing concentration. Importantly, such congestion also limits the use of existing infrastructure, the weaving section downstream. This behaviour thus affects both safety and operational aspects. The potential tool for managing motorways effectively and efficiently is cooperative intelligent transport systems (C-ITS). This research investigates a lane-change distribution advisory application based on C-ITS for weaving vehicles in weaving sections. The objective of this research is to alleviate the lane-changing concentration problem by coordinating weaving vehicles to ensure that such lane-changing activities are evenly distributed over the existing weaving length. This is achieved by sending individual messages to drivers based on their location to advise them when to start their lane change. The research applied a microscopic simulation in AIMSUN to evaluate the proposed strategy’s effectiveness in a one-sided ramp weave. The proposed strategy was evaluated using different weaving advisory proportions, traffic demands and penetration rates. The evaluation revealed that the proposed lane-changing advisory has the potential to significantly improve delay.

A C-ITS based lane changing advisory for weaving sections

This study examines the benefits of Cooperative Intelligent Transport Systems (C-ITS) in weaving sections. The research proposes a lane-changing advisory application to alleviate the lane-changing concentration in weaving sections by coordinating weaving vehicles. While non-weaving vehicles travel as normal, weaving vehicles are monitored and advised through personalized messages based on their destination lane. The findings of this research, derived from a microscopic simulation in AIMSUN, reveal that the proposed strategy has the potential to improve delay significantly and that it can be applied to any existing one-sided weaving sections.

Modelling, calibrating, and validating car following and lane changing behaviour

Car following (CF) and lane changing (LC) are two primary driving tasks observed in traffic flow, and are thus vital components of traffic flow theories, traffic operation and control. Over the past decades a large number of CF models have been developed in an attempt to describe CF behaviour under a wide range of traffic conditions. Although CF has been widely studied for many years, LC did not receive much attention until recently. Over the last decade, researchers have slowly but surely realized the critical role that LC plays in traffic operations and traffic safety; this realization has motivated significant attempts to model LC decision-making and its impact on traffic. Despite notable progresses in modelling CF and LC, our knowledge on these two important issues remains incomplete because of issues related to data, model calibration and validation, human factors, just to name a few. Thus, this special issue will focus on latest developments in modelling, calibrating, and validating two primary vehicular interactions observed in traffic flow: CF and LC.

Freeway traffic oscillations : microscopic analysis of formations and propagations using Wavelet Transform

In this paper we identify the origins of stop-and-go (or slow-and-go) driving and measure microscopic features of their propagations by analyzing vehicle trajectories via Wavelet Transform. Based on 53 oscillation cases analyzed, we find that oscillations can be originated by either lane-changing maneuvers (LCMs) or car-following behavior (CF). LCMs were predominantly responsible for oscillation formations in the absence of considerable horizontal or vertical curves, whereas oscillations formed spontaneously near roadside work on an uphill segment. Regardless of the trigger, the features of oscillation propagations were similar in terms of propagation speed, oscillation duration, and amplitude. All observed cases initially exhibited a precursor phase, in which slow-and-go motions were localized. Some of them eventually transitioned into a well developed phase, in which oscillations propagated upstream in queue. LCMs were primarily responsible for the transition, although some transitions occurred without LCMs. Our findings also suggest that an oscillation has a regressive effect on car following behavior: a deceleration wave of an oscillation affects a timid driver (with larger response time and minimum spacing) to become less timid and an aggressive driver less aggressive, although this change may be short-lived. An extended framework of Newell’s CF is able to describe the regressive effects with two additional parameters with reasonable accuracy, as verified using vehicle trajectory data.

Comparative evaluation of microscopic car-following behavior

Microscopic traffic-simulation tools are increasingly being applied to evaluate the impacts of a wide variety of intelligent transport, systems (ITS) applications and other dynamic problems that are difficult to solve using traditional analytical models. The accuracy of a traffic-simulation system depends highly on the quality of the traffic-flow model at its core, with the two main critical components being the car-following and lane-changing models. This paper presents findings from a comparative evaluation of car-following behavior in a number of traffic simulators [advanced interactive microscopic simulator for urban and nonurban networks (AIMSUN), parallel microscopic simulation (PARAMICS), and Verkehr in Statiten-simulation (VISSIM)]. The car-following algorithms used in these simulators have been developed from a variety of theoretical backgrounds and are reported to have been calibrated on a number of different data sets. Very few independent studies have attempted to evaluate the performance of the underlying algorithms based on the same data set. The results reported in this study are based on a car-following experiment that used instrumented vehicles to record the speed and relative distance between follower and leader vehicles on a one-lane road. The experiment was replicated in each tool and the simulated car-following behavior was compared to the field data using a number of error tests. The results showed lower error values for the Gipps-based models implemented in AIMSUN and similar error values for the psychophysical spacing models used in VISSIM and PARAMICS. A qualitative drift and goal-seeking behavior test, which essentially shows how the distance headway between leader and follower vehicles should oscillate around a stable distance, also confirmed the findings.

Reproduction and behavior of plateau pikas (Ochotona curzoniae Hodgson) under predation risk: A field experiment

The mixture of the feces and urine of the red fox (Vulpes vulpes Linnaeus) was used to increase the perception of predation risk of plateau pikas (Ochotona curzoniae Hodgson) in the field. The influence of the predation risk on the reproduction and behavior of plateau pikas was examined through comparing reproductive characteristics and five different kinds of behavior between treatment and control plots. The results showed that 1) the body weight of the pikas was not significantly different between treatment and control plots. 2) The reproductive period of the pikas extended from March to later August in both treatment and control plots. The pregnant ratio, developed testes ratio, reproductive success and sex ratio of the pikas were not significantly different between the treatment and control plots. 3) The pikas increased their observing and calling frequencies and decreased their moving and feeding frequencies when exposed to red fox's feces and urine. 4) The increased red fox's feces and urine had no influence on the behavior of the pikas when the number of their natural enemies increased; the pikas obviously increased the observing frequencies and sharply decreased the calling frequency so as to decrease the direct predation risk. 5) There were no significantly behavioral differences between males and females as well as between adults and young. 6) The results reject the hypothesis 1 that the red fox's feces and urine as indirect predation risk suppresses the reproduction of the pikas and support the hypothesis 2 that the pikas can make decision by changing behavior to avoid the predation risk they encountered whenever.

The influence of mindfulness meditation on angry emotions and violent behavior on Thai technical college students

Introduction: Violence among technical college students is a significant issue in Thailand, South East Asia, and yet few interventions are available for use with this group. In this study the outcomes of a culturally appropriate intervention, mindfulness meditation (MM), on anger and violent behavior are reported. The MM intervention was delivered over three consecutive weeks to technical college students (n = 40) and the effects compared to a comparison group (n = 56) who attend classes as usual. Methods: Both the intervention and comparison group completed a series of validated self-report measures on aggressive and violent behavior perpetration and victimization on three occasions (pre-intervention, 1 month and 3 month post-intervention). Results: Program participants reported lower levels of anger expression at one month follow-up, but there were no observed group. ×. time interactions for self-reported violent behavior. Rates of victimization changed over time, with one interaction effect observed for reports of being threatened. Conclusions: MM may have the potential to improve emotional self-control, but is likely to only impact on violent behavior when this is anger mediated.

The behavior and natural history of Chartergellus, a little-known genus of neotropical social wasps (Vespidae Polistinae Epiponini)

This study reviews published data on the behavior and natural history of Chartergellus and presents the first observations on social interactions in this genus of tropical swarm-founding wasps. Observations of Chartergellus golfitensis in Costa Rica and C. punctatior in Colombia showed that queens perform a post-oviposition egg-guarding vigil, and a bending display like that characteristic of epiponine social wasps that lack consistent morphological differences between workers and queens and have caste determination in the adult stage. Young, old, and queen (egg-laying) females of C. golfitensis showed small differences that indicate color changes with age, and structural differences that could be due to seasonal or colony-cycle changes in developmental conditions, but do not rule out the possibility of pre-adult caste determination, a phenomenon that needs to be carefully distinguished from pre-adult caste bias. Sexual dimorphism and the behavior of males at the nest in C. golfitensis is described, as well as the aggressive and avoidance behavior of females toward males. Nest structure in both species is as described previously for Chartergellus species, but some anomalies and their possible evolutionary significance are discussed. Cell initiation by an egg-laying queen, a behavior never seen by workers, and by a young female with slightly developed ovaries, may be vestiges of ancestral solitary reproductive traits where developed ovaries are associated with cell construction. © 2010 Dipartimento di Biologia Evoluzionistica dell'Università, Firenze, Italia.

The contexts of scratching behavior and postconflict behavior in squirrel monkeys (Saimiri sciureus)

Self-directed behavior (SDB), such as scratching, is a reliable indicator of emotional arousal in non-human primates. In contrast, affiliative behavior, such as social grooming, has been shown to have a calming effect in primates and reduce arousal. In order to test whether the expression of SDB was related to arousal, the scratching behavior of eight captive squirrel monkeys (Saimiri sciureus) was compared across four social contexts (huddling, proximity to others, solitary and post-conflict). In addition,rates of scratching were examined before and after affiliative behavior during the postconflict context. I tested for this effect by using the post-conflict/matched control(PC/MC) method in which post-conflict (PC) behavior of an animal is compared to thebehavior of the same animal in a baseline, nonaggressive situation or a matched control(MC). Context and associated scratching data were obtained from a total of 98 hours of focal sample data. Scratching was significantly lower while animals were huddling thanthe other two contexts. Scratching rates while solitary were significantly higher than those occurring while animals were in proximity. Scratching was also higher in PC than MC. Following conflict, animals were significantly more likely to make contact withthird parties not involved in aggression. Most of these (79%) were a third party approaching a combatant. Further, scratching rates decreased following post-conflict third party contacts and the decrease was not due to a general decrease in scratching thatmight have been occurring after the aggressive interaction. Huddling behavior appears to reduce arousal in squirrel monkeys and may act as a tension-reduction mechanism. The elevated scratching in the solitary context may suggest that squirrel monkeys may be engaged in activities while solitary, such as vigilant behavior that may increase arousal. The third party post conflict affiliative contacts observed were the first such interactions observed in squirrel monkeys. The fact that these third contacts reduced scratching ratesin the combatants indicates that 'consolation' may have been demonstrated in this species. The overall pattern of results suggested that scratching was reliable behavioral indicator of anxiety in squirrel monkeys. These results indicate that overt behavior can be used to assess emotional states in this and other species, acting as a mediator to understanding how emotions regulate social behavior.