want some information on four wheel steering ,its wirking n contrustion also.

4 wheel steering quad

Quadrasteer is the name of a four wheel steering system developed by Delphi Corporation while under the ownership of General Motors for use in automobiles. It was available as an option on GM's full-size pickup trucks and C2500 Suburbans for model years 2002 through 2005.

Such a system is a tremendously useful feature to people who tow regularly, as it enables a person to turn their vehicle in much tighter spaces than if they had a regular steering system. It is costly, adding as much as $5,600 initially (later reduced to about $2,000 and then $1,000 to boost acceptance) to the price of the vehicle. Many people, especially those who tow boats, fifth wheels, or other large equipment found the system useful enough to justify the expense.