Toyota Adds Value in Crown, Doubling Datacomm Traffic

Datacomm traffic is double what it used to be in the vehicular local area network (LAN) in the new Crown model, announced on February 18, 2008 by Toyota Motor Corp of Japan. The car boasts four "world's first" technologies, as well as a host of new functions. And implementing all of these new functions has doubled the data communications traffic.
What does double the load really mean? Most of the new technology in the Crown was not implemented through newly developed hardware, such as sensors or actuators. The increased traffic, in fact, is directly tied to the fact that Toyota Motor has been concentrating on software development.

A comparison of the new and old Crown models shows that there is indeed more hardware in the new one, but a closer look reveals that the composition of the hardware is about the same as that in the Lexus LS460, released in 2006. The Crown offers new technologies not found in the LS460, in spite of having the same hardware, because of software technologies interconnecting various pieces of equipment. For example, existing cameras and brake systems have been linked by software to a function to detect if the driver's eyes are open or shut, making possible a brand new pre-crash safety system.
Stop Line Locations, etc

One of the pieces of newly developed software that stands out the most is technology to interconnect the car navigation system and vehicular control functions. Toyota Motor first used car location data from the car navigation system to automatically change gears in 1998. The technology has been evolving since, and the new Crown comes with two new related functions. Map data is used to provide driver assistance in braking as the car approaches a stop line; the car automatically changes gears as it approaches an expressway junction, and more.

Technologies to utilize car navigation systems in other vehicular applications will no doubt continue to evolve, but a look at these functions reveals a few problems. The car navigation system serves as the sensor to measure the car's current location, and Toyota Motor feels that location precision is still too low. The braking assist function to help the driver bring the car to a halt before reaching the stop line, for example, demands an accurate grasp of the distance to the stop line. This type of function is impossible with low-precision car navigation systems, for which reason Toyota Motor has included information including speed limits, crosswalks and other features of various roads, along with the locations of the stop lines. Stop line locations, however, were individually measured by hand.

source:
http://techon.nikkeibp.co.jp /article/HONSHI/20080428/151147/