Drivers’ Braking Behavior Affected by Cognitive Distractions: An Experimental Investigation with a Virtual Car Simulator

Abstract

In this study, a cohort of 78 university students performed a driving experience in a virtual urban scenario, by means of a car driving simulator, to examine effects of a planned hands-free mobile phone conversation on young drivers’ braking behaviors. To this aim, a control group was left free to drive without any imposed cognitive task. An experimental group faced the same scenario while engaged in a phone call. The conversation via earphones was arranged to diminish the amount of cognitive resources allocated to the driving task. For both groups, the analyses focused on the moment at which a child entered a pedestrian crossing from a sidewalk. The results of a mixed two-way ANOVA showed the presence of a significant difference for distracted and non-distracted drivers with the absence of gender-related differences across the two groups. Distracted participants assumed lower initial speeds, took the first action to stop at shorter distances from the zebra crossing, and had more difficulty in keeping speed variations under control. These findings suggest that the distraction induced by the use of earphones may induce risk compensation behaviors and delay pedestrian perception. Moreover, the effects on the participants' braking behavior suggest that the procedure adopted to increase cognitive load, based on a story retelling, is an effective method to analyze the impact of hands-free cellphone use on driving skills in a car simulation experiment.

Talking on the Phone While Driving: A Literature Review on Driving Simulator Studies

“…Some of the studies presented two experiments: [ 64 , 65 , 66 , 67 ], or split the sample in two or three: inexperienced drivers vs. experienced drivers [ 68 , 69 , 70 ], young vs. older participants [ 71 , 72 , 73 ], novice drivers and young adults [ 74 ], young-, middle-, old-age [ 75 ], experienced, novice, and older drivers [ 67 ], but the total number of participants was considered in this analysis. Other studies used a control group in their experiments: [ 63 , 76 , 77 , 78 , 79 , 80 , 81 , 82 ].…”

Surrogate Safety Measures Prediction at Multiple Timescales in V2P Conflicts Based on Gated Recurrent Unit

“…The car-driving simulator at the Road Laboratory (product name AutoSim 1000-M) has been already validated and successfully used for studying the drivers' braking behavior affected by cognitive distractions [21]. The simulator cockpit is made with real car parts (e.g., dashboard, steering wheel, pedals, gear lever, handbrake, driver seat, seatbelt) of an Italian city car.…”

“…In the Lab's AutoSim 1000-M driving simulator [21], it was possible to record a dataset for the GRU models' development by observing test participants' behavior toward two planned traffic encounters: a boy/girl entering a crosswalk from the curb. The simulated scenes (Figure 1) were set in a typical urban environment on a course that could take about 15 min to be completed, considering the 50 km/h speed limit.…”

“…Conversely, at the end of the simulation test, a second questionnaire about the discomfort perceived while driving was completed by each participant to identify and remove from the cohort those drivers who had experienced excessive annoyance. The simulation test procedure just presented has been drawn from relevant literature that provided for its validation [21,27,31]. The recruited cohort includes 19 females and 41 males, with a mean age of 24.0 (SD 3.43) and 24.1 (SD 1.91) years and a mean non-verbal intelligence quotient (IQ) [32] of 33.4 (SD 2.50) and 33.9 (SD 1.66), respectively.…”

“…Since the two traffic participants may enter a collision course during the encounter process, such a conflict has the potential to end up in a collision. For example, the latter would occur if the driver's attention levels, his/her ability to control the vehicle, or the vehicle's dynamic state were not adequate for a safe stopping behavior [21].…”