Laboratories and Data Acquisition Systems
The traditional laboratories at VTTI are housed in two buildings totaling more than 52,000 square feet. Building I is 30,000 square feet and houses office, laboratory, and garage facilities. Low-service laboratories include facilities dedicated to driver interface development, eye-glance data reduction, lighting research, accident analysis, accident database analysis, pavement research, and traffic simulation. The National Surface Transportation Safety Center for Excellence building comprises 22,000 square feet of office and laboratory space and was occupied in July 2006. VTTI expanded its on-site capacity by 7,000 square feet of warehouse space and housing for a shock tube lab, a paint booth facility, and a lighting lab. An additional 24,400 square-foot annex was opened during August 2013.
Data Acquisition Systems (DASs)
The VTTI-developed data acquisition systems (DASs) have been designed to collect and store large amounts of continuous naturalistic data from the driving environment, including video, vehicle network information, and additional sen¬sor information that can include radar, GPS, and acceleration.
Data collected from various onboard systems are processed and stored in the DAS, which is similar to a “black box” unit found in commercial airplanes. The DAS features are configurable and typically include:
- An arm-based core with video processing on a digital signal processor chip;
- Additional sensors, such as accelerometers, gyroscopes, and magnetometers;
- Video with H.264 video/audio compression and multi-channel binary data synchronization;
- Doppler-based front and rear radar;
- Controller area network 2.0B, VPW, PWM, and ISO vehicle network interfaces; and
- Removable, high-capacity, shock-resistant hard drives for data retrieval.
Via its multi-camera system, the DAS can collect information about a range of variables. These cameras record multiple views that can include forward, rearward, and internal views (such as over-the-shoulder, face, and pedal areas). Across the sensor package, data parameters can be customized to include such variables as:
- Vehicle network data, such as speed, airbag deployment, brake use, throttle position, turn signaling, and many other elements;
- Environmental factors, such as weather, light¬ing, glare, and temperature;
- Presence of nearby objects and their relative speed obtained via radar and optical technologies; and
- Other data, such as sound, vibration, accelera¬tion, and turning rate.
Current DAS iterations include the Next Generation (NextGen) DAS and the MiniDAS. The NextGen DAS is fully customized on two circuit boards, is easily configurable, and features machine-vision and lane-tracking software. The MiniDAS includes a connection to the vehicle network, two video channels, GPS, a nine-axis inertial measurement unit (accelerometer, gyroscope, and magnetometer), is expandable with sensor modules via WiFi or Bluetooth, and is compatible with dedicated short-range communication radios. All of the MiniDAS features fit within a system roughly the size of a sandwich and enable naturalistic studies for all vehicle sizes operating on the roadway, from motorcycles and bicycles to tractor-trailers.