James R. Sayer

Naturalistic Census of Cell Phone Use

One hundred eight drivers participated in a naturalistic field operational test. Each participant drove an instrumented passenger car for 6 weeks. Video data from the first week of driving for each participant were visually scored for all instances of cell phone use. These instances were divided into cell phone calls (conversations) and cell phone interactions that were not calls (visual or manual tasks involving the cell phone). Researchers examined 1,382 conversations and 2,149 visual or manual tasks. Participants were engaged in cell phone conversations 6.7% of all driving time and in visual or manual tasks involving a cell phone 2.3% of all driving time. Overall, conversations had a mean duration of 2.6 min, and participants engaged in conversations at a rate of 1.5 conversations per hour. Younger drivers were significantly more likely to be engaged in either type of cell phone task than older drivers and significantly more likely to be engaged in visual or manual tasks than middle-aged drivers. Drivers were more likely to initiate conversations and visual or manual tasks when stopped than at higher speeds; this finding may suggest a level of self-regulation. Furthermore, the finding suggests that estimates of crash risk that are based on assumptions that behavior observed in stopped vehicles translates to behavior in moving vehicles is incorrect and will result in overestimates of driver engagement in cell phone use.

Heavy-Truck Drivers’ Following Behavior With Intervention of an Integrated, In-Vehicle Crash Warning System: A Field Evaluation

Objective: This study is designed to evaluate heavy-truck drivers’ following behavior and how a crash warning system influences their headway maintenance. Background: Rear-end crashes are one of the major crash types involving heavy trucks and are more likely than other crash types to result in fatalities. Previous studies have observed positive effects of in-vehicle crash warning systems in passenger car drivers. Although heavy-truck drivers are generally more experienced, driver-related errors are still the leading factors contributing to heavy-truck-related rear-end crashes. Method: Data from a 10-month naturalistic driving study were used. Participants were 18 professional heavy-truck drivers who received warnings during the last 8 months of the study (treatment period) but not during the first 2 months (baseline period). Time headway and driver’s brake reaction time were extracted and compared with condition variables, including one between-subjects variable (driver shift) and five within-subjects variables (treatment condition, roadway types, traffic density, wiper state, and trailer configuration). Results: The presence of warnings resulted in a 0.28-s increase of mean time headway with dense on-road traffic and a 0.20-s increase with wipers on. Drivers also responded to the forward conflicts significantly faster (by 0.26 s, a 15% enhancement) in the treatment condition compared with responses in the baseline condition. Conclusion: Positive effects on heavy-truck drivers’ following performance were observed with the warning system. Application: The installation of such in-vehicle crash warning systems can help heavy-truck drivers keep longer headway distances in challenging situations and respond quicker to potential traffic conflicts, therefore possibly increasing heavy-truck longitudinal driving safety.

The conspicuity of first-responder safety garments

INTRODUCTION This study compared the conspicuity of three types of first-responder safety garments (NFPA 1971-2007 turnout gear coats, and ANSI/ISEA 107 and 207 safety vests). METHOD Participants drove instrumented vehicles on a closed track during both daytime and nighttime, indicating when they could first detect pedestrians in a simulated emergency response scene. Pedestrians wore one of the safety garments and stood on either side of the emergency scene, facing or perpendicular to oncoming traffic, and either stationary or walking in place. RESULTS All three garment standards provided equal levels of conspicuity, in that the distances at which the pedestrians were detected were equivalent. Time of day was a significant factor, with longer mean detection distances being observed in daytime. Pedestrian orientation was significant, with mean detection distances being longest when facing traffic. Pedestrian motion did not result in significant differences in detection distance. DISCUSSION The results suggest that all three garment types studied are equivalent in making first responders conspicuous as pedestrians when working an emergency response scene in close proximity to traffic. IMPACT ON INDUSTRY Whether an NFPA or ANSI/ISEA compliant is worn, first responders are equally likely to be detected by passing motorists, and as such these garments should be considered to be equivalent.

The roles of garment design and scene complexity in the daytime conspicuity of high-visibility safety apparel.

INTRODUCTION This study examines the effects of high-visibility garment design on daytime pedestrian conspicuity in work zones. Factors assessed were garment color, amount of background material, pedestrian arm motion, scene complexity, and driver age. METHOD The study was conducted in naturalistic conditions on public roads in real traffic. Drivers drove two passes on a 31-km route and indicated when they detected pedestrians outfitted in the fluorescent garments. The locations of the vehicle and the pedestrian were recorded. RESULTS Detection distances between fluorescent yellow-green and fluorescent red-orange garments were not significantly different, nor were there any significant two-way interactions involving garment color. Pedestrians were detected at longer distances in lower complexity scenes. Arm motion significantly increased detection distances for pedestrians wearing a Class 2 vest, but had little added benefit on detection distances for pedestrians wearing a Class 2 jacket. DISCUSSION Daytime detection distances for pedestrians wearing Class 2 or Class 3 garments are longest when the complexity of the surround is low. The more background information a driver has to search through, the longer it is likely to take the driver to locate a pedestrian--even when wearing a high-visibility garment. IMPACT ON INDUSTRY These findings will provide information to safety garment manufacturers about characteristics of high-visibility safety garments which make them effective for daytime use.

Consumer Acceptance of Adaptive Cruise Control following Experience with a Prototype System

Reactions to adaptive cruise control (ACC) were solicited from drivers following use of an ACC equipped vehicle for one hour in an actual highway environment. Participants impressions were obtained through questionnaires, administered immediately following the exposure, and later in focus groups. Individuals of varying age and conventional cruise control usage took part in the study. The issues of comfort, safety, ease-of-use, and estimated worth were addressed. While participants offered favorable responses towards ACC, despite having limited safety concerns, they were willing to pay surprisingly little for the added convenience provided. The issues of driver over-dependency on technology, system reliability, and customized features appear to warrant additional investigation to overcome consumers hesitation towards purchasing and using ACC and similar forms of advanced vehicle control systems.

Real-World Frequency of Use of Automotive Lighting Equipment

Abstract This study provides information about average annual use of the following automotive lighting equipment by U.S. drivers: low- and high-beam headlamps, turn signals, and stop, back-up, parking, sidemarker, and tail lamps. The data were collected as part of a naturalistic field study of crash warning systems. Eighty-seven randomly selected drivers from southeastern Michigan were provided with instrumented research vehicles (11 identical 2003 Nissan Altimas) for periods averaging 26 days and instructed to drive the vehicles as their personal vehicles. The results are presented for each lamp type in terms of the average annual hours of use and minutes used per 100 km driven. These findings are discussed in relation to the rated life of various lamps and the average life of vehicles in the U.S. License plate, parking, sidemarker, and tail lamps were the most frequently used automotive lighting equipment, averaging just over 100 hours per year. The least used lamps were back-up lamps, which were used less than five hours per year. Average annual hours of lamp use decreased with increasing driver age. While rates of use for stop, turn signal, and back-up lamps were similar for females and males, male drivers accrued 34 percent more hours of nighttime driving than female drivers, while using their high beams about half as often.

Real-world effects of using a phone while driving on lateral and longitudinal control of vehicles

INTRODUCTION Technologies able to augment human communication, such as smartphones, are increasingly present during all daily activities. Their use while driving, in particular, is of great potential concern, because of the high risk that distraction poses during this activity. Current countermeasures to distraction from phone use are considerably different across countries and not always widely accepted/adopted by the drivers. METHODS This study utilized naturalistic driving data collected from 108 drivers in the Integrated Vehicle-Based Safety Systems (IVBSS) program in 2009 and 2010 to assess the extent to which using a phone changes lateral or longitudinal control of a vehicle. The IVBSS study included drivers from three age groups: 20–30 (younger), 40–50 (middle-aged), and 60–70 (older). RESULTS Results from this study show that younger drivers are more likely to use a phone while driving than older and middle-aged drivers. Furthermore, younger drivers exhibited smaller safety margins while using a phone. Nevertheless, younger drivers did not experience more severe lateral/longitudinal threats than older and middle-aged drivers, probably because of faster reaction times. While manipulating the phone (i.e., dialing, texting), drivers exhibited larger lateral safety margins and experienced less severe lateral threats than while conversing on the phone. Finally, longitudinal threats were more critical soon after phone interaction, suggesting that drivers terminate phone interactions when driving becomes more demanding. CONCLUSIONS These findings suggest that drivers are aware of the potential negative effect of phone use on their safety. This awareness guides their decision to engage/disengage in phone use and to increase safety margins (self-regulation). This compensatory behavior may be a natural countermeasure to distraction that is hard to measure in controlled studies. Practical Applications: Intelligent systems able to amplify this natural compensatory behavior may become a widely accepted/adopted countermeasure to the potential distraction from phone operation while driving.

Using naturalistic driving data to examine drivers' seatbelt use behavior: Comparison between teens and adults.

PROBLEM Teens and young drivers are often reported as one driver group that has significantly lower seatbelt use rates than other age groups. OBJECTIVE This study was designed to address the questions of whether and how seatbelt-use behavior of novice teen drivers is different from young adult drivers and other adult drivers when driving on real roads. METHOD Driving data from 148 drivers who participated in two previous naturalistic driving studies were further analyzed. The combined dataset represents 313,500 miles, 37,695 valid trips, and about 9500 h of driving. Drivers did not wear their seatbelts at all during 1284 trips. Two dependent variables were calculated, whether and when drivers used seatbelts during a trip, and analyzed using logistic regression models. RESULTS Results of this study found significant differences in the likelihood of seatbelt use between novice teen drivers and each of the three adult groups. Novice teen drivers who recently received their drivers licenses were the most likely to use a seatbelt, followed by older drivers, middle-aged drivers, and young drivers. Young drivers were the least likely to use a seatbelt. Older drivers were also more likely to use seatbelts than the other two adult groups. The results also showed that novice teen drivers were more likely to fasten their seatbelts at the beginning of a trip when compared to the other three adult groups. SUMMARY Novice teen drivers who were still in the first year after obtaining their drivers license were the most conservative seatbelt users, when compared to adult drivers. PRACTICAL APPLICATION Findings from this study have practical application insights in both developing training programs for novice teen drivers and designing seatbelt reminder and interlock systems to promote seatbelt use in certain driver groups.

Longitudinal driving behavior with integrated crash-warning system

This study created the most extensive set of naturalistic data that has ever been gathered on the following behavior of drivers when interacting with a forward crash-warning system. For the purposes of this paper, data from the naturalistic driving study of the Integrated Vehicle-Based Safety System (IVBSS) program were used. IVBSS data collected from a total of 108 drivers, representing 81,163 steady state following events and 20,096 forward conflict events were extracted and compared. Drivers were from three age groups (younger, middle-aged, and older) and balanced between two gender groups. Three objective measures were used in this study: mean time headway, minimum time to collision, and proportion of time drivers spent in time headway of 1 s or less. Drivers used the research vehicles for 40 days, with the system not activated for the first 12 days and activated for the following 28 days. A linear mixed model was used for the data analysis. Results of this study show that drivers have a tendency to follow more closely when the warning system is activated. It is recommended that a visual display for feedback on real-time safe following distance may help drivers keep a safer distance. This study also observed age-related self-regulation behavior when other vehicles were being followed and showed that older drivers tended to follow farther away from the leading vehicle.

INTELLIGENT CRUISE CONTROL : ISSUES FOR CONSIDERATION

This paper addresses issues associated with intelligent cruise control systems, including seat belt lock-out systems, foot placement sensing and adjustable headway.