Disconnect Between Driver Behavior/Performance Studies and Crash Experience: Lessons from the Study of Young/Inexperienced Drivers

The quantitative measurement of driver behavior has been central to much of the systematic research underlying highway safety issues during the past forty years. It has contributed to the way in which we design roads, vehicles, training programs, signs and markings, and intelligent transportation systems. Yet the methods we use to conduct driver behavior experiments may result in a disconnect with the circumstances under which crash events occur. This is particularly evident in problems related to young, inexperienced drivers. This paper discusses some of the systematic biases that characterize the quantitative driver behavior research base regarding youthful drivers. Some broader implications for the general study of driver behavior and performance are then considered

Deciding to be Distracted

This project investigated the decision process involved in a driver’s willingness to engage in various technology-related and non-technology tasks. The project included focus groups and an on-road study, both employing participants who used in-vehicle technologies to at least some degree, from four age groups: teen, young, middle, and older. The focus groups discussed the perceptions, motivations, attitudes, and decision factors that underlie driver choices. The on-road study had two phases: an on-road drive and a take-home booklet. Participants drove their own vehicles over a specified route. They did not actually engage in in-vehicle tasks, but at specified points they rated their willingness to engage in some specific task at that time and place. Eighty-one different situations (combination of in-vehicle task and driving circumstances) were included. Further information was collected in the take-home booklet regarding the participant’s familiarity with various in-vehicle technologies, additional situations for willingness and risk ratings, stated reasons underlying ratings, and self-ratings of certain aspects of driving behavior and decisionmaking style. Together, the focus groups and on-road study provided complementary findings about how drivers decide when to engage in potentially distracting tasks. Driver willingness to engage in various in-vehicle tasks was related to technology type, specific task attributes, driving conditions, personal motivations, driving style, and decision style. Specific project findings were related to potential countermeasure approaches, including public education; driver or device user training; user interface design; needs for warnings and information; criteria for function lock-outs; and driver assist system criteria

A Look in the (Driver’s) Mirror: Use of Portable Electronic Devices While Driving by the Driver Safety Research Community

As the frequency and diversity of use of portable electronic devices by drivers has increased, so have the roadway safety concerns associated with such multitasking. It has been argued that the driving public needs to be better informed about the risks of multitasking, and if they were so informed, people would restrict such practices. Yet various surveys show that in general the public seems to recognize that the use of portable electronic devices while driving does impose significant risk. This study reports the results of a survey of highway and vehicle safety professionals, a group highly informed about the problem and often engaged in efforts on this very issue. It would be instructive to see how this group behaves in terms of its own portable electronic device use while driving. An internet survey was distributed to members of two prominent professional society technical groups in driver safety. The survey revealed substantial cell phone use while driving, moderate text messaging, and little engagement in such activities as social networking, internet browsing, or e-book reading. Members of this expert community actively provided guidance about portable electronic device use while driving to others, including children and teens, family, and friends

Replicating Test Track Protocols in a Simulator; What Needs to be Matched?

Many different experimental methods are used to evaluate driving performance as well as to evaluate the effectiveness of various vehicle safety systems but the results often do not match between different experimental approaches. This study aimed to determine the extent to which results can be matched between a driving simulator and a test track when carefully designed studies are used to replicate findings. This study collected simulator data on the National Advanced Driving Simulator (NADS) at the University of Iowa to replicate findings concerning Forward-Crash-Warning interface effectiveness at the Vehicle Research and Test Center (VRTC), East Liberty Ohio. The simulator used a virtual replica of the test track as well as a road course. Event choreography and scanning behavior were compared. Results indicate that results from the simulator were similar to those obtained on the test track. This indicates simulators can replicate findings for the test track and are a valuable tool. Careful experimental design is required to match the event choreography to insure an appropriate comparison. An exact match of the driving environment was not needed for this interface evaluation to obtain comparable results. The extent to which matching motion cues was not evaluated and may prove challenging in simulators without motion systems

Perception of Approaching Motorcycles by Distracted Drivers May Depend on Auxiliary Lighting Treatments: A Field Experiment

A field experiment was conducted in daylight with 32 participants to determine whether left turning drivers’ gap acceptance in front of approaching motorcycles depends on the motorcycle’s forward lighting treatment. Five experimental lighting treatments including a modulated high beam headlamp, or the low beam headlamp plus pairs of low-mounted auxiliary lamps, high-mounted auxiliary lamps, both high- and low-mounted auxiliary lamps, or low-mounted LED lamps were compared to a baseline treatment with only the low beam headlamp illuminated. Participants viewed the approaching traffic stream (including the motorcycle) on an active roadway and indicated when it would be safe (and not safe) to initiate a left turn across the opposing lanes. Participants also shared their attention with a secondary visual distraction task that took their eyes off the forward roadway. Participants did not know that the purpose of the study was to measure their responses to approaching motorcycles. Based on participants’ indications of the last safe moment to turn, the mean temporal safety margin provided to the approaching motorcycle did not differ significantly between any of the experimental lighting treatments and the baseline treatment. However, having either low-mounted auxiliary lamps or modulated high beam lamps on the motorcycle significantly reduced the probability of obtaining a potentially unsafe short safety margin as compared to the baseline lighting treatment. Overall, the results suggest that enhancing the frontal conspicuity of motorcycles with lighting treatments beyond an illuminated low beam headlamp may be an effective countermeasure for daytime crashes involving right-of-way violations

Passenger Age and Gender Effects on Adult Driver Fatal Crash Rate

Driver behavior and crash rates vary with the presence of passengers but the details of this relationship are not well understood. The literature generally does not take into account the characteristics of passengers, yet effects on crashes may vary dramatically with passenger age and gender. This study estimated the amount of exposure (driving miles) done by various driver age/gender categories with various combinations of passengers. Statistical imputation techniques were used to derive travel estimates for various pairings using data from the 2001 National Household Travel Survey. Crash frequencies for every pairing were obtained from the Fatality Analysis Reporting System and were used to compute fatal crash rates (per 10 million trip miles). The findings reported here focus on adult (21 and older) drivers. The results show that drivers of a given type (age/gender group) show dramatically different crash rates as a function of passenger type. Some passenger types are associated with fatal crash rates higher than that with no passenger, while other passenger types are associated with lower crash rates. The details of this relationship depend to some degree on driver characteristics. Crash rates for different driver age/gender groups overlap substantially based on the passenger, so that the “best” and “worst” driver groups are passenger-specific. For adult male drivers, female passengers are generally associated with lower crash rates. For male drivers, there is a higher crash rate with a male passenger of a given age than with a female passenger of the same age, even for child passengers

Seabed AUV Offers New Platform for High-Resolution Imaging

A number of marine biological, geological, and archaeological applications share the need for high-resolution optical and acoustic imaging of the sea floor [Ballard et al., 2002; Greene et al., 2000; Shank et al., 2002]. In particular,there is a compelling need to conduct studies in depths beyond those considered reasonable for divers (∼50 m) down to depths at the shelf edge and continental slope (∼1000–2000 m). Some of the constraints associated with such work include the requirement to work off of small coastal vessels or fishing boats of opportunity,and the requirement for the vehicle components to be air-shippable to enable inexpensive deployments at far-flung oceanographic sites of interest

Dynamic network analysis of contact diaries

Analyzing two-mode networks linking actors to events they attend may help to uncover the structure and evolution of social networks. This classic social network insight is particularly valuable in the analysis of data extracted from contact diaries where contact events produce — and at the same time are the product of relations among participants. Contact events may comprise any number of actors meeting at a specific point in time. In this paper we recall the correspondence between two-mode actor–event networks and hypergraphs, and propose relational hyperevent models (RHEM) as a general modeling framework for networks of time-stamped multi-actor events in which the diarist (“ego”) simultaneously meets several of her alters. RHEM can estimate event intensities associated with each possible subset of actors that may jointly participate in events, and test network effects that may be of theoretical or empirical interest. Examples of such effects include preferential attachment, prior shared activity (familiarity), closure, and covariate effects explaining the propensity of actors to co-attend events. Statistical tests of these effects can uncover processes that govern the formation and evolution of informal groups among the diarist’s alters. We illustrate the empirical value of RHEM using data comprising almost 2000 meeting events of former British Prime Minister Margaret Thatcher with her cabinet ministers, transcribed from contact diaries covering her first term in office (1979–1983)

Older Driver Perception-Reaction Time for Intersection Sight Distance and Object Detection, Volume I: Final Report

DTFH61-90-C-00038Four on-road experiments investigated whether the assumed values for driver perception-reaction time (PRT) used in AASHTO design equations adequately represent the range of actual PRT for older drivers. The Case III (stop controlled) intersection sight distance (ISD) experiment found that older drivers did not have longer PRT than younger drivers; 85th percentile PRT closely matched the AASHTO design equation value of 2.0 s. In the stopping sight distance (SSD) experiment involving brake reaction times to an unanticipated event (crash barrel suddenly rolling toward roadway), there were apparent differences in the distribution of PRT among age groups. Younger drivers accounted for most of the fastest PRT, but there were no age differences in the 50th or 85th percentiles. All observed PRT were encompassed by the current AASHTO design value of 2.5 s. The decision sight distance (DSD) experiment measured when drivers recognized the need to make a lane change maneuver, from the first visibility of the roadway cue used by the driver. Although observed DSD values were generally longer with increasing driver age, the 85th percentile PRT for all age groups were well below AASHTO design assumptions. The final experiment collected judgments about the acceptability of gaps and lags in traffic. Younger subjects accepted shorter gaps and rejected lags later than older subjects. Based on these findings, and consideration of the implications of changes in PRT for sight distance requirements, no changes to design PRT values, based on older driver performance, were recommended for ISD, SSD, or DSD. Alternative models for ISD, based on gap acceptance or lag rejection, were explored. Based on limited data, it is not clear whether these models offer any significant benefits to the current AASHTO model