Absofuckingloutley not for both situations. Everyone on getbig that drinks and is old enough to drive has been over the limit while driving before. It's an absolute fact so dont even try to get on your soap box and preach about those killed by drunk drivers. The way the law is constituted now is perfectly fine IMO.
Does the death penalty stop murder? No, because if you want to kill someone, chances are your not thinking about getting caught or being put to death.
Do stiff drug penalties prevent drug use? Think Rockerfeller drug laws. If you want to get high, your going to get high and fuck the consequences. In many Asian and Muslim countries there are death penalties for drugs, and yet, some people still manage to be executed every year for drug use.
Drag Racing is a much more serious and preventable evil than DUI IMO. You can be over the limit by accident. Its impossible to accidentely drag race with another willing participant on a public street or highway.
As long as nobody is injured ( which would make the charges higher anyway) and no property is destroyed, DUI is a largely victimless crime where occasionally some dumbass goes too far and kills or maims someone. However, the same can be said for careless drivers that kill people while sober. Higher penalties are going to do nothing except ruin peoples lives and satisfy the MAAD lobby.