The solution consists of an Eye (camera + IR camera) connected to a mini arduino (or similar) that watches the driver by looking at its face and detecting if eyes are opened. (see http://www.visagetechnologies.com/html5/ ) . When your eyes are closed fox X seconds, a notification sounds loudly. Possible addition: Heart rate sensor in the steering wheel so when the HR drops(you fall asleep) the system notifies you as well.
Technically this seems a pretty simple device to build. If the insurance companies cooperate (cheaper insurance when using this device) This should be a financially viable product.
What do you think of this?