DriveSafety CDS-250 Driving Simulator: VA Mobile
In 2010, as a result of collaborative work with the Institute for Mobility, Activity, and Participation, the North Florida/ South Georgia Veterans Administration obtained a DriveSafety CDS-250. This simulator was the first of its kind to be integrated into a wheelchair lift equipped 2010 Dodge Sprinter van. This mobile simulator provides a unique opportunity to reach people for simulator-based driving assessment, or behind-the-wheel training.
The CDS-250 console and controls are based on Ford Focus sedan. The simulator provides an automotive control environment with standard driver controls and computerized information systems. “Live” controls include a steering wheel with active force feedback, automatic transmission, turn signals, and gas and brake pedals. A high-fidelity sound system creates digital audio simulation of the sounds of driving.
Simulator Operating System
The host computer is based on real-time Linux operating system on an off-the-shelf, Intel-based computer. It provides the simulator’s vehicle dynamics, instrumentation input/output processing, scenario control, and data collection. Real-time driving and traffic simulation is provided by DriveSafety’s Vection™ run-time simulation software. Vection™ is a deterministic real-time simulation system. This run-time software package includes advanced vehicle dynamics, scenario control with both scripted and autonomous traffic simulation, flexible data collection, audio and visual subsystems, and integrated support for cab instrumentation and control loading. Vection™ provides an extremely powerful environment to provide realistic driving simulation experiences and measure the desired results. The simulator utilizes high-speed (2400Hz) multi-body vehicle dynamics to represent real world vehicle performance and handling characteristics. Drives are created with a combination of ambient and scripted traffic. Traffic interacts realistically with other vehicles based on human behavior/decision models and real-time physics-based vehicle dynamics calculations. If specific behavior is desired, such as collision avoidance, vehicles and other entities can be issued script commands through the use of triggers (e.g., car pulls in front of driver at a certain point in the drive), or other scenario tools including timers, or routes (e.g., incorporating unprotected left turns).
The simulator utilizes high resolution textured graphics to deliver high visual quality without sacrificing performance. All geometry is designed to run efficiently in real-time, maintaining a 60 Hz update rate in most situations and with 48 msec measured system latency. The simulators’ virtual drives utilize user-definable databases created with the HyperDrive™ Authoring Suite’s library of over 400 driving environment tiles or the pre-programmed Simetrx™ drives. Roadways and traffic control devices are geometrically correct and modeled to highway design standards. The host computer controls three graphics channel computers running high performance graphics accelerators that are responsible for the scene rendering. The driving scene is presented on a triple-screen display using three 20-inch panels for a 65 degree field of view (FOV). FOV compression allows the rendered scene to easily accommodate a 110 degree horizontal view. Scene rendering also includes real-time views for a head-up display rear-view mirror and side-view mirrors.
The simulator has real-time data collection capabilities and collects a wide range of data at rates up to 60 Hz. Over 80 standard performance measures are provided via output files. These include speed, lane position, reaction time, steering, and use of brake or accelerator.
Performance Measure Examples
- Lane Position – The lane offset in meters within the current lane.
- Steering – The steering input value in degrees.
- Velocity – The speed of the subject vehicle in meters per second.
- Collision variables – Object the vehicle is colliding with, angle of collision and collision velocity.
Several acclimation drives were designed to train drivers on aspects of simulator operation and help them adjust to driving in a simulator. The simulator drives address lane keeping on straight and curved roads, changing lanes, use of side and rear-view mirrors, and stopping.
In addition to standard acclimation drives, three drives were created specifically to meet the needs of VA patients and research subjects. These drives are: (1) Town and Country, (2) Residential and Suburban, and (3) City and Highway.
Drive 1 – Town and Country (8 minutes)
This drive starts in a residential neighborhood on a narrow 2 lane road with no markings and a 25 mph speed limit. The neighborhood has light traffic, parked cars, and pedestrians. The drive then proceeds into commercial area with 4 lane road at 35 mph followed by a rural 2 lane highway through hilly terrain at 45 mph. The drive ends in a second neighborhood with a residential narrow 2 lane road at 25 mph. This drive has three challenges: (1) at four-way stop sign intersection, man on bicycle proceeds from right violating subject’s right of way and crossing path of travel, (2) on 45 mph highway section, a lane is closed due to a roadside incident, and the driver must yield and use an on-coming traffic lane to pass, (3) parked car pulls out suddenly in congested neighborhood area.
Drive 2 – Residential and Suburban (6 minutes)
This drive starts in a residential neighborhood on a narrow 2 lane road with no markings and a 25 mph speed limit. This road section has a visually cluttered environment with traffic, parked cars, trash cans at the curb and some pedestrians, dog, etc. The driver encounters four-way stop intersections. The drive transitions to a rural 2 lane road at 45 mph, and then to a commercial 4 lane road at 35 mph with busy intersections. The drive ends at a strip mall. There are three challenges: (1) a pedestrian enters the crosswalk of the street the driver is turning on to, (2) an unprotected left turn at an intersection with traffic in opposing lanes, and (3) lead vehicle brakes suddenly because of a cyclist (or alternate event, a slow vehicle being passed cuts off subject lane from the right).
Drive 3 – City and Highway (10 minutes)
This drives starts in an urban area presenting multi-lane (4+) and narrow city streets as well as moderate traffic and pedestrians. The drive proceeds to freeway driving, with some enhancements of road scene (e.g., roadside debris, disabled vehicle with tow truck). The drive ends in a commercial area (strip malls etc.). This drive has three challenges: (1) a parked car pulls out in front of the driver, (2) the driver must make an unprotected left turn, and (3) a pedestrian steps from behind a parked car into the path of the driver.