Despite shipping with a standard VW/Audi flip-out key, the A8 does incorporate a full keyless entry/start system. This means that you should never have to take the key out of your pocket - as you grab the door handle the door will unlock, while each handle also has a button to lock the car. If you're particularly paranoid, you can still lock the car using the key fob, just to be sure.
What is puzzling is that although the A8 has keyless start, via a button mounted in the centre console, it still has an ignition slot and can still be started by turning the key in said slot. Also curious is the fact that the button you press to start the car doesn't also stop the engine, there's a separate button for that. And you have to press the stop button a second time to engage the steering lock. It all seems a little convoluted to me.
There's no traditional handbrake, with Audi instead opting for an electronic parking brake, just like the Renault Laguna Coupe. However, unlike the Renault, the parking brake on the A8 did not engage automatically when the engine was stopped, nor did it disengage when the car was put into drive and the accelerator pedal pressed. Of course a traditional handbrake would do neither of those things either, so it shouldn't be too much of a chore to remember to engage and disengage it manually.
With a car this size parking will be a worry for many owners so it's good to see that Audi has taken this into account. The A8 is equipped with parking sensors front and rear, while there's also a reversing camera mounted just above the rear number plate. As soon as reverse is engaged the music volume drops and the screen displays the view from the reversing camera.
To aid your parking you get both audible and visual cues of obstacles, while there are guidelines superimposed onto the camera view that you're meant to line up with your desired parking place. The default mode is for reversing into a parking bay, but you can also switch to a parallel parking mode. The system does work pretty well, but I've got to say that I still feel more comfortable doing it the old fashioned way using my wing mirrors - the audible warnings are always nice on a car this size though.
Audi has also attempted to address some of the hazards associated with motorway driving by incorporating Side Assist and Lane Assist systems into the A8. The former comprises a cluster of yellow LEDs integrated into the wing mirror housings. These will light up when there's a vehicle either side of you, potentially in your blind spot. If you indicate to change lane they will flash to tell you that there's another car next to you, or travelling at speed in your intended lane. Lane Assist is there to stop you drifting unintentionally into another lane by making the steering wheel vibrate if you cross the white lines.