18. January

New version available: Version 0.5 (Revision 50) (https://svn.pcuie.uni-due.de/CARS/)

24. June 2009

New tutorials online: Creating new elements for CARS and Playing Sounds in CARS - check out the tutorial page.

CARS

CARS is an open source PC-based driving simulator tool for evaluating driver distraction. It is designed to support the early stages of a development process for in-car systems by providing a concrete basis for making design decisions.

CARS consists of three main components: the driving simulation tool, a map editor for creating the route according to specific requirements with different street elements, speed limit signs, etc. and an analysis tool for calculating driver’s performance.

Driving Simulation Tool

Driving Simulation Tool Screenshot

The driving simulation tool is implemented in Java and is based on the JMonkeyEngine (www.jmonkeyengine.com). JMonkeyEngine (JME) uses the Lightweight Java Game Library (LWJGL) (lwjgl.org) as an interface to OpenGL. Thus, the driving simulator is available for all platforms that are able to run a Java Virtual Machine and render OpenGL scenes. In addition to JME, we use the JME physics engine (https://jmephysics.dev.java.net/); this framework simulates physical interactions in a world scene, like gravity. To create the virtual driving environment, the simulation tool first reads the map/world information stored in a text file and generated by the map editor. Then the simulation tool renders a view of the world from a driver’s perspective. The initial view is determined when setting up the map in the editor. A user can then start the driving task and drive using the controllers. For analyzing the driving performance the position in the virtual world (x, y, z), speed, time, steering wheel position, pedal position, breaking activity and deviation of the lane position is stored in a log file with a rate of 20Hz.

Map Editor

Map Editor Screenshot

The map editor offers the opportunity to create several routes with different types of road conditions e.g., a straight road or a winding road. It has a graphical user interface which allows an easy, intuitive way to create a map with a series of mouse clicks. Elements which are provided at the moment:

  • straight street elements
  • curves
  • intersections
  • signs (speed limit, give way, etc. )

Additional elements can always be added, but additionally to graphics each map elements must have corresponding models in the simulation. The map editor generates a text file with a matrix describing the elements. This is used by the simulation tool to create the virtual world.

Analysis Tool

Analysis Tool Screenshot

The analysis tool calculates the following values:

  • mean distance to the racing line
  • standard deviation of the mean distance to the racing line
  • mean lateral speed
  • mean speed
  • standard deviation of speed
  • mean deviation of the steering wheel position
  • frequency of steering correction
  • standard deviation of gas pedal position
  • frequency of speed corrections, and off-road time

These parameters are the basics for analyzing results of user tests and eventually for calculating the driver distraction. The analysis tool provides the parameters, nevertheless you must determine which of these data are most relevant for each test. Two data files generated by the simulation tool can be read by the analysis tool at the same time to show the comparisons of different rides, e.g. one set while on the phone and one without distraction. The data are represented graphically on the left side of the Analysis Tool’s GUI and calculated data values are shown on the right side.