so

1 -12 volt car batterys are lethal

2-110 volts(ac) is as dangerous as 220-240

3- 55 volts is dangerous

Not sure what you are trying to say here, but you could infact come into contact with 10,000volts and not be killed, yet stick your tongue accross a 9 volt battery and die.

It is all about current, any current over 10 mA will cause shock, the most lethal is between 100 and 200 mA. This is because your heart operates in that region and can be stopped by these lower currents. Any current higher than 200 mA will still at worst kill but at the least will cause burns.

This is a simple explaination.