Texas Driver's Handbook, Section 10: Alcohol and Drugs
How alcohol and drugs affect driving, the legal limit, zero tolerance for minors, implied consent and the penalties.
Summary written by MyPermitExam from the official handbook, Revised January 2026. Not a copy of the handbook. Checked Oct 2026. Not affiliated with the DMV. Texas Driver Handbook (DL-7)
Key rules
- Adults are intoxicated at 0.08 BAC; drivers under 21 may not have any detectable alcohol (zero tolerance). p. 55
- Only time sobers you up, about one drink per hour; coffee, cold showers and exercise do not work. p. 56
- An open container in the passenger area on a public highway is illegal even when parked; the fine is up to $500. p. 56
- Refusing a breath or blood test suspends an adult's license for 180 days; failing it with 0.08 or more, for 90 days. p. 58
- A 12-ounce beer, a 1.5-ounce shot in a mixed drink and a 5-ounce glass of wine have about the same alcohol. p. 58