Michael Goodman was the NHTSA Task Order Manager for this project. 16. Abstract This research effort provided valuable insight into the nature and severity of lane changes in a naturalistic driving environment. Sixteen commuters who normally drove more than 25 miles (40 km) in each direction participated. The two research vehicles were a sedan and an SUV; each participant drove each vehicle for ten days. Data gathering was automatic, and no experimenter was present in the vehicle. There were 8,667 lane changes observed over 23,949 miles of driving, making this the largest known data collection effort for the study of lane changes. Analysis of the full data set resulted in many interesting findings regarding the frequency, duration, urgency, and severity of lane changes in regard to maneuver type, direction, and other classification variables. A subset of the full data set (500 lane changes) was then analyzed in greater depth using the sensor data collected by the instrumented vehicle. The sampled lane changes were generally of the more severe and urgent types since these are the cases in which a lane change collision avoidance system is likely to be of greatest help.Variables analyzed for the sampled lane changes included turn signal use, braking behavior, steering behavior, eye glance patterns, and forward and rearward area analysis. The concept of a safety envelope for lane changes was then developed using the forward and rearward area analyses. Finally, the data were used to provide recommendations for designers of lane change CAS in terms of display location and activation criteria. Overall, the research described in this report provides insight into the behaviors and parameters associated with lane changes, while the naturalistic data archive has the potential to address other questions related to driving behavior.17.

Previous laboratory and simulator research has indicated that hazard detection skills and abilities are less developed among novice drivers compared with experienced adult drivers. Novices tend to miss some relevant cues and may be less able to process important elements in the environment while driving. As was found with other research methods, it was hypothesized that novices would have lower hazard detection skills and will react less appropriately to hazards than older and more experienced drivers.Three hazard perception scenarios were simulated on a test track and data were collected on newly licensed teen drivers (within 2 weeks of licensure) and a comparison group of adults. The scenarios included a hidden stop sign, hidden pedestrian, and hidden pedestrian with lane closure (this last included a text-messaging task). Discrete quantitative performance metrics were evaluated for this analysis, including: 1) Did the participant glance at the potential hazard (e.g., stop sign, pedestrian)? 2) Did the participant stop (for the stop sign scenario)? 3) Did the participant show signs of indecision, caution, or awareness (for all hazards)?Significant differences between teen drivers and more experienced adult drivers were found in a combined hazard detection analysis. Results indicate that the adult drivers observed hazards and demonstrated overt recognition of hazards more frequently than the teen drivers. Results indicated that a large portion of teen drivers failed to disengage from peripheral task engagement in the presence of hazards. The results will later be compared to naturalistic data for the same set of drivers to see whether these test track results are predictive of real-world behavior.

This paper describes preliminary results of naturalistic lane change distribution, frequency, and duration data collected unobtrusively from 16 commuters using instrumented vehicles. The study was designed to improve upon previous data collection methods and support crash avoidance system development. A total of 8,667 lane changes (including unsuccessful maneuvers) were identified and classified in terms of severity, urgency, maneuver type, and success/magnitude. The total miles driven was 23,949 (38,542 km) with an average of 37.4 miles (60.2 km) per commute and 2.76 miles (4.44 km) per lane change. More than 37% of lane changes were due to a slow vehicle ahead. The mean duration for 7,192 single lane changes was 6.28 seconds with a standard deviation of 2.0. Analysis revealed no significant effects for duration. For frequency, significantly more lane changes were completed by drivers on the interstate, perhaps due to traffic density, while sedan drivers made significantly more lane changes than SUV drivers. A significant driver type (vehicle normally driven) by route (interstate or highway) interaction was discovered, perhaps due to driving style. A gender by route interaction was also found.

Eyeglance behavior and scanning patterns may be learned as a driver gains experience and lead to greater situation awareness on the part of the driver. This may help to explain differences observed in the safety records of novice teen and experienced adult drivers. For example, new drivers may focus almost exclusively on the road ahead and spend little time scanning the vehicle's mirrors. However, a novice driver performing a secondary task may spend more time with his or her eyes on the task than on the road, because of unfamiliarity with the vehicle or inexperience with consequences of long glances away from the forward view. For this study, 18 novice teen (under 17.5 years old and within 4 weeks of licensure) and 18 experienced adult drivers performed a set of in-vehicle tasks on a test track. A baseline driving segment was also included. Measures consisted of percentage of eyes-off-road (EOR) time, number of glances, and mean single-glance time. Results showed that teens glanced at the rearview mirror significantly fewer times than did adults, both during baseline driving and while performing in-vehicle tasks. Teens also had a significantly higher percentage of EOR time than adults had while performing a challenging reading task. The novice teen drivers spent more of their overall EOR time looking at the task display (e.g., cell phone), whereas adults used some EOR time to check mirrors or windows. Overall findings indicate that novice teens may lack the situation awareness of experienced adults.

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