Is a substantive difference? Or is it a matter of jurisdictional terminology?
I think today it’s just a matter of the jurisdictional terminology being abbreviated. In the 1970s in New York, they referred to two offenses, Driving While Intoxicated and Driving Under the Influence, the latter being a lesser included offense of the former and defined as something like driving erratically as a result of the consumption of alcohol or another intoxicant. The break point between them was .08 of course.
Actually, in New York, the official terms are “Driving While Intoxicated” (DWI) and “Driving With Ability Impaired” (DWAI). DWAI is for a BAC of 0.5-0.7%; DWI is for anything about 0.7%. Plus there’s Aggravated DWI if you’re over 0.15%.
Other states use DUI instead of DWAI.
Just terminology. And only civilian terminology, too – the official writing on your citation, and used in court will be listed as a violation of statute number 123.45 or something similar.
But in some states, like Polycarp mentioned, there are different common terms for driving drunk vs. driving impaired.
Here in Minnesota, land of 10,000 lakes (actually more), we also have offenses for boating while intoxicated. And (for the Amish & Hutterite areas) Buggy Driving while intoxicated.
This was inacted in 1971. Driving while intoxicated still had a threshold of 0.15 percent by weight of alcohol, but they were debating cutting it to 0.12 percent.
In Indiana, it’s actually OWI (Operating While Intoxicated). And then there are five basic variations: OWI (basic), OWI while endangering a person (a higher class of misdemanor), OWI with BAC .08 or above, OWI with BAC .15 or above, and OWI with Schedule I or II controlled substances. The basic offense (OWI) will be subsumed by the others if convicted (as a violation of double jeopardy). Of course, there are more serious (read felonies) charges if someone is injured or if you have a prior OWI in the last five years.
This is only for Indiana, though.
In Texas, DWI is what’s frequently called DUI everywhere else, driving with a BAC of .08 or higher. There is a less serious charge called DUI, though, that only minors can commit - if you’re under 21 you’re DUI if you drive with any amount of alcohol in your system up to .08 (past that you’re DWI, same as an adult).