### Question
What does alcohol concentration mean?


### Answer
**Alcohol concentration** has the following meaning in *23 U.S.C. § 164*:

> grams of alcohol per 100 milliliters of blood or grams of alcohol per 210 liters of breath

#### Citation:
  - *23 U.S.C. § 164*
  - Heading: **CHAPTER 1-FEDERAL-AID HIGHWAYS**

