Tennessee DUI Laws Explained

By Javier Marín, Editor·Last reviewed September 2026·How we check this

A Tennessee DUI conviction under T.C.A. § 55-10-401 triggers two parallel processes: a criminal case in General Sessions or Criminal Court, and an administrative license action by TN DSHS. Both move on independent tracks. Tennessee imposes one of the strictest mandatory minimum jail sentences in the country — 48 consecutive hours on a first offense, with no judicial discretion to suspend the minimum below that floor.

The legal threshold

Adults 21+: 0.08% BAC.
Drivers under 21: 0.02% BAC under Tennessee's zero-tolerance "Underage Driving While Impaired" law (T.C.A. § 55-10-415).
Commercial drivers (CDL): 0.04% BAC.
Aggravated DUI threshold: 0.20% BAC under T.C.A. § 55-10-402, which extends the mandatory minimum jail sentence to 7 days.
Impairment evidence: Tennessee also charges DUI on impairment evidence below 0.08% — the prosecution doesn't need a specific BAC to prove "the defendant's ability to operate was impaired by alcohol or drugs."

Implied-consent law

Tennessee is an implied-consent state under T.C.A. § 55-10-406. Refusing the breath, blood, or urine test triggers an automatic 1-year administrative license revocation on a first refusal, separate from any criminal-case revocation. Repeat refusals get progressively longer:

First refusal: 1 year.
Second refusal within 10 years: 2 years.
Third refusal within 10 years: 5 years.
Refusal in conjunction with a crash causing injury or death: 5 years.

Refusal cases are handled by the General Sessions Court at the time of arraignment; the driver has the right to challenge the refusal at a hearing.

First-offense criminal penalties

A first-offense DUI in Tennessee is a Class A misdemeanor under T.C.A. § 55-10-402(a)(1) carrying:

Mandatory minimum 48 hours in jail, served consecutively (not "weekend jail" — actual continuous custody). Statute does not allow this minimum to be suspended.
Maximum jail sentence of 11 months and 29 days.
A fine of $350-$1,500 plus court costs and victim-impact fund assessments.
1-year license revocation by TN DSHS (separate from any administrative refusal revocation).
Mandatory completion of DUI School (alcohol and drug safety education).
Probation, typically 11 months 29 days, with random alcohol screens.
Mandatory ignition interlock device (IID) for any first-offense DUI with BAC at or above 0.08% — the IID is required during any restricted-license period and for at least 6 months after reinstatement.

Aggravated DUI (BAC 0.20%+)

Under T.C.A. § 55-10-402(a)(1)(A), a first-offense DUI with a BAC at or above 0.20% is an "aggravated" first offense and carries:

Mandatory minimum 7 days in jail (not 48 hours).
Higher fine range — typically $500-$1,500 plus enhancements.
Mandatory IID for the longer of 1 year or the full revocation period.

The restricted license pathway

After conviction, the driver may petition the sentencing court for a restricted driver license under T.C.A. § 55-10-409. The restricted license is limited to:

Travel to and from work, school, court-ordered alcohol education, and medical appointments.
Required IID on every vehicle driven during the restricted period.
SR-22 financial responsibility filing maintained for the full revocation period.

The restricted license is granted at the discretion of the sentencing court. TN DSHS issues the restricted license card after the court order is filed and the IID is documented.

Diversion and DUI

Tennessee offers two diversion paths — Pre-Trial Diversion (PRD) and Judicial Diversion — for non-violent first offenders. DUI itself is not eligible for either diversion program under T.C.A. § 40-15-105. The General Assembly specifically excluded DUI from diversion in 1989. Other related charges (reckless driving, public intoxication) may be eligible for diversion through plea negotiation.

Repeat offenses

Tennessee uses a 10-year lookback for sentencing-enhancement purposes:

Second offense within 10 years: Class A misdemeanor with 45-day mandatory minimum jail, $600-$3,500 fine, 2-year license revocation, and mandatory IID for at least 1 year.
Third offense within 10 years: Class E felony with 120-day mandatory minimum jail, $1,100-$10,000 fine, 6-year license revocation, mandatory IID for at least 2 years, and vehicle forfeiture under T.C.A. § 55-10-403(k).
Fourth or subsequent offense within 10 years: Class E felony with 150-day mandatory minimum jail, $3,000-$15,000 fine, 8-year license revocation, mandatory IID for at least 3 years.

Aggravating factors

Crash causing serious bodily injury — Class D felony "Vehicular Assault" under T.C.A. § 39-13-106 (2- to 12-year prison range).
Crash causing death — Class B felony "Vehicular Homicide by Intoxication" under T.C.A. § 39-13-213 (8- to 30-year prison range).
Aggravated Vehicular Homicide — Class A felony where the offender has two or more prior DUIs OR the BAC was 0.20%+ AND there was a death (15- to 60-year prison range).
Child passenger under 18 — separate Child Endangerment DUI charge.
Prior DUI within the lookback window — sentencing enhancements as above.

DUI-Drugs

Tennessee charges DUI for impairment by any drug under the same § 55-10-401 statute, including marijuana (illegal under Tennessee state law), prescription medication, and controlled substances. Drug-DUI cases use Drug Recognition Expert (DRE) testimony plus blood toxicology. Tennessee does not have a per-se nanogram limit for THC; the prosecution must prove actual impairment.

Insurance fallout

A DUI conviction triggers SR-22 financial responsibility filing for at least 3 years on reinstatement. Tennessee insurers run the conviction through their own rating systems — there is no state-uniform surcharge schedule like Massachusetts's SDIP. Most Tennessee carriers add a 50-100% surcharge sustained over 3-5 years on a first DUI. See Tennessee insurance for SR-22 carriers and the financial-responsibility framework.