Error 404--Not Found

From RFC 2068 Hypertext Transfer Protocol -- HTTP/1.1:

10.4.5 404 Not Found

The server has not found anything matching the Request-URI. No indication is given of whether the condition is temporary or permanent.

If the server does not wish to make this information available to the client, the status code 403 (Forbidden) can be used instead. The 410 (Gone) status code SHOULD be used if the server knows, through some internally configurable mechanism, that an old resource is permanently unavailable and has no forwarding address.

Error 404--Not Found

Error 404--Not Found

From RFC 2068 Hypertext Transfer Protocol -- HTTP/1.1:

10.4.5 404 Not Found

The server has not found anything matching the Request-URI. No indication is given of whether the condition is temporary or permanent.

If the server does not wish to make this information available to the client, the status code 403 (Forbidden) can be used instead. The 410 (Gone) status code SHOULD be used if the server knows, through some internally configurable mechanism, that an old resource is permanently unavailable and has no forwarding address.

Focus on Electronics
GM researches collision warning

GM is in the midst of an automotive crash-warning research project with the U.S. Department of Transportation (DoT) and primary partner Delphi Delco Electronics Systems. Begun in the summer of 1999, the focus is on helping the driver avoid crashes by making the car smarter about the traffic and environment around it. The first half of the five-year, $35 million Intelligent Vehicle Initiative (IVI) research project involves development and testing of prototype vehicles equipped with crash-avoidance technology.

GM and suppliers are currently working on a Buick LeSabre prototype that should be complete in about a year. GM displayed a LeSabre engineering development vehicle equipped with collision-warning-system hardware at the U.S. DoT/SAE National Intelligent Vehicle Initiative (NIVI) Meeting in July. The second half of the program will include the building of two pilot vehicles for further testing and validation, and a field test in southeast Michigan. Ten production Buick LeSabres outfitted with the system will be built in 2002 for real-world testing.

"This will be the most comprehensive field test of automotive collision-avoidance systems ever undertaken in the United States," said Dr. Lawrence D. Burns, Vice President for GM Research & Development and Planning, the lead GM unit for the program. "Our belief is that the best crash protection we can provide is to help people avoid the collision altogether. No company has developed a sophisticated, multi-sensor collision-warning system like this and then tested it in real-world conditions. We're understanding more and more the critical link between vehicle safety and driver behavior, and we're working to improve both."

Sensors and instruments on the car will measure road conditions and environmental factors and feed real-time information to decision-making software that will alert the driver to hazards in the vehicle's forward path and adjust the car's adaptive cruise control. Once system design and integration is complete, GM plans to turn over test vehicles for consumers to drive for 10 months in real-world conditions. Each of about 120 drivers would have unrestricted use of a test car for two to four weeks while data are collected. The University of Michigan Transportation Research Institute (UMTRI) would help screen, select, and orient the drivers from across southeast Michigan, and then would perform data collection and analysis.

The LeSabres will be fitted with forward radar, forward vision, mapping systems, global positioning systems, and adaptive cruise control—all tied together by sophisticated software and computers. The system even keeps tabs on driver actions to estimate "distraction level" and response times. When a threat is detected, the system will either alert the driver or, if adaptive cruise control is engaged, take control of the accelerator and brakes to slow the vehicle.

Key components of the test car include:

  • Vehicle sensors—To monitor compass heading, lateral and longitudinal acceleration, yaw rate, steering angle, and wheel speeds.
  • Vehicle data—To monitor windshield wiper settings; turn signal; headlight-switch, accelerator-pedal, and brake-pedal positions; PRNDL setting; traction control information; and road surface roughness.
  • Radar—A forward-looking radar system detects and tracks obstacles and moving vehicles ahead, including those that may be temporarily obscured by another vehicle. Software assesses whether a target may be a bridge or vehicle, evaluates the paths of other vehicles to estimate the road's geometry, and estimates which lane the host vehicle is in.
  • Vision-based lane tracking—A video system estimates the lane alignment and curvature or offset of the road up to 90 m (100 yd) ahead. It watches the relationship between the vehicle and the lane and the angle the vehicle is headed.
  • Map-based road geometry—A Global Positioning System receiver and dead-reckoning navigation produce an estimate of the vehicle's position, which is compared to digital map databases. This gives the system a sense of the road ahead, where the car is on the road, and any key features along the way such as hills, merging lanes, tunnels, or curves. These data also produce an estimate of the car's motion.
  • Yaw-based path estimation—A yaw-rate sensor (an accelerometer that detects changes in the vehicle's direction) is coupled with data on speed, acceleration, and steering wheel angle to predict the vehicle's path.
  • Data fusion—Decision-making software assesses each part of the data to decide what is most believable. It looks at estimated road curvature, the relationship of the host vehicle to its surroundings, a prediction of the vehicle's path, road conditions including visibility, driver distraction level, and driver response time.
  • Target selection—Comparing the vehicle's estimated path with the location and paths of surrounding targets, software singles out the object that would be hit first if the car's motion did not change.
  • Threat assessment—The results of the data-fusion and target-selection processes result in an estimate of the threat of a collision, and prompt either a change in cruise control and braking or a timely warning to the driver to make adjustments.

Rear-end crashes account for more than 25% of all injury collisions, according to the U.S. DoT, and most are caused by inattention, tailgating, or speeding—factors the joint research project could alleviate. Other companies are experimenting with adaptive cruise control and simple collision-avoidance systems that integrate a forward-looking laser or radar with a few sensors, but none has attempted the breadth and complexity of systems that the joint U.S.-GM research entails, according to the company. Information streaming from more than 20 sensors and systems will be assessed and analyzed instantly by the custom-written software. The aim of the study is to develop and integrate these technologies and accelerate the introduction of a cohesive vehicle package, according to Burns.

Kevin Jost

AEI September 2000

Error 404--Not Found

Error 404--Not Found

From RFC 2068 Hypertext Transfer Protocol -- HTTP/1.1:

10.4.5 404 Not Found

The server has not found anything matching the Request-URI. No indication is given of whether the condition is temporary or permanent.

If the server does not wish to make this information available to the client, the status code 403 (Forbidden) can be used instead. The 410 (Gone) status code SHOULD be used if the server knows, through some internally configurable mechanism, that an old resource is permanently unavailable and has no forwarding address.