Can someone explain to me what the rationale of open alcohol container laws is? I don't get it, I totally understand laws that don't allow you to drive with a certain amount of alcohol in your blood (ie anti-drink driving), but, for example, in Australia and the UK it is legal (although not advisable) to drive whilst drinking a beer provided you are below the legal limit. However, it seems that if you merely have an open alcohol container in your vehicle, you can get pinged in the US. What is this law protecting against? Can a passenger drink alcohol in a car whilst you are driving sober?