When the iPhone 4S was first announced, Siri was one of the features that caught most peoples attention. Although it might not be all that useful day to day when in an office, it certainly has its uses when travelling about when you might not be able to pick up your phone and use it. With that in mind, Autoblog decided to test Siri with a number of bluetooth car systems to see if it works over a handsfree kit.
In short, the answer is yes, it does work. Siri is able to function in a car as when pressing and holding the home button the car looks at it as a phone call and allows you to interact with Siri. The main problems are the quality of the microphone(s) you use and the system in general. If you have a quiet car and good quality mics then Siri works well handsfree, but if not you might struggle a little to have it understand you.
Take a look at the video below to see Siri being tested in one of the vehicles.