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C H A P T E R 2
Existing Studies Using In-Vehicle Video Cameras
Digital video cameras have rapidly evolved since the 1990s. · Longitudinal acceleration was greater than 0.25 g ;
Tapeless video cameras make it possible to use relatively small · Critical incident button was pressed;
hardware equipment to record and save large-sized data. The · Vehicle crossed solid lane border;
quality of images has greatly improved and the editing process · Time to collision (TTC) of 4 s or less;
is simplified, allowing nonlinear editing systems to be widely · PERCLOS (percent eyelid closure) of 8% for 1 min;
deployed on desktop computers. Even though image sizes are · Driver subjectively assessed drowsiness as "extremely
small, it is easy to recognize the movements of targets and the fatigued or difficult to stay awake" or did not respond;
ongoing background environment and acquire the information · Lane departure followed by a steering event (disabled if
needed. turn signal was on); and
Because of their advanced capability, digital cameras have · A baseline data file, collected every 45 to 75 min.
recently been used in multiple transportation safety research
projects to capture drivers' behaviors in a naturalistic driving In addition to the video-recorded data, the data collected
environment. Table 2.1 lists the studies discussed in this report. included vehicle network information (speed, accelerator,
Because of difficulties associated with older data collection brake pedal, and steering wheel); environmental monitoring
methods (e.g., videocassette tapes), emphasis was placed on (temperature, illumination, vibration, and noise in decibels); X,
research conducted during recent years. A short description of Y, and Z acceleration; and lane orientation using a SafeTRAC
each project follows Table 2.1. lane tracking system, as well as some data generated after the
data reduction, such as eyeglance behavior and road type and
Project 1: Sleeper Berth geometry (13).
Conducted by the Virginia Tech Transportation Institute
Project 2: Automotive Collision
(VTTI), this study examined drivers' sleeping habits and
Avoidance System Field
drowsiness with respect to crash risk. Two tractor trailers were
Operational Test
instrumented and loaned to trucking companies for their
extended runs. Data from 41 drivers were used. In total, 47 The Automotive Collision Avoidance System (ACAS) FOT was
males and 9 females were involved in the study. The average led by General Motors (GM) under a cooperative agreement
age was 43, with ages ranging from 28 to 63. On average, the with the U.S. Department of Transportation (DOT). The FOT
drivers had 13 years of driving experience. Data collection runs involved exposing a fleet of 11 ACAS-equipped Buick LeSabre
lasted up to 240 h (6 to 10 days). passenger cars to 12 months of naturalistic driving by drivers
Continuous video data were recorded on four channels: from southeastern Michigan. The ACAS included a forward
driver's face, forward roadway, left rear, and right rear. Data crash warning (FCW) and an adaptive cruise control (ACC)
were saved only for predefined critical incidents. If a specified system. The FOT's goal was to determine the feasibility of
kinematic trigger was activated, the data acquisition system the ACAS for widespread deployment from the perspective of
(DAS) saved video and parametric data for 90 s before and 30 s driving safety and driver acceptance. Ninety-six drivers partic-
after the event. Predefined events included: ipated, resulting in 137,000 mi of driving. Results indicated
that the ACC was widely accepted by drivers, but the accept-
· Steering wheel moved faster than 3.64 rad/s; ance of the FCW was mixed (due to false alarms) and not found
· Lateral acceleration was greater than 0.3 g; to be significantly related to the FCW alert rate.
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