The question is : Do people become intoxicated faster if they mix their drinks with diet soda vs. regular soda. The anser is : diet mixed drinks metabolizes alcohol faster than drinks mixed with regular soda. When the body metabolize alcohol it converts it to be absorbed in the blood stream, it does not eliminate it. The study below indicates that people become intoxicated faster when mixing drinks with diet soda, it does not indicate the length of time people are intoxicated.
http://thechart.blogs.cnn.com/2013/02/05/alcohol-and-diet-soda-may-equal-a-bad-mix/
CC, thank you for the link. Actually, the linked article doesn't mention metabolizing alcohol. It says that the stomach treats a sugary mixer as food, slowing the process of alcohol getting into the blood stream, whereas with a diet drink it will pass through more quickly. I'm not trying to give you a hard time on this, but I did want to understand. Again, thanks for the link.