NJSA 39:4-50 Lawyers

39:4-50 – Driving While Intoxicated (Elements & BAC Tiers Explained)

N.J.S.A. 39:4-50 makes it illegal to operate a motor vehicle while under the influence of alcohol, narcotics, or drugs. This statute broadly defines “operation” and sets tiered penalties that escalate with BAC level and prior offenses.

New Jersey’s primary drunk driving law is N.J.S.A. 39:4-50, which makes it illegal to operate a motor vehicle while intoxicated by alcohol, narcotics, hallucinogens, or any habit-producing drug. To convict someone, prosecutors must prove two elements: operation of a vehicle and intoxication.

This statute is strict because “operation” does not always mean the car was moving. Courts have held that sitting in the driver’s seat with the keys in the ignition or the engine running can be enough. In State v. Daly (1973), the New Jersey Supreme Court ruled that a person found behind the wheel of a parked car with the engine running could still be convicted of DWI. This reasoning was later reinforced in State v. Mulcahy (1987) and State v. Thompson (2020), where the court confirmed that “operation” can be proven even without actual driving if the circumstances show intent and control.

The second element, intoxication, is usually measured through blood alcohol concentration (BAC). New Jersey enforces a tiered BAC system:

• Under .08% – You can still be convicted if officers show you were impaired through field sobriety tests or observations.
• .08–.10% – This is the per se legal limit.
• .10–.15% – Higher fines and longer interlock requirements.
• .15% and above – Mandatory IID installation during suspension and extended interlock afterward.

The law also applies to drug impairment, where prosecutors may rely on toxicology reports or Drug Recognition Expert (DRE) evaluations to establish that narcotics, marijuana, or even prescription medications impaired safe operation.

Related Resource: Learn more about BAC and testing procedures on our Blood Alcohol Content in NJ page.

39:4-50 – What the State Must Prove to Convict

To convict under N.J.S.A. 39:4-50, the State must prove both that the defendant operated a vehicle and that they were intoxicated, typically shown through BAC tests or officer observations.

Prosecutors must establish two elements beyond a reasonable doubt under N.J.S.A. 39:4-50:

1. Operation of a motor vehicle doesn’t always mean driving. Courts have ruled in State v. Daly and State v. Thompson that being in the driver’s seat with the engine running or having control of the vehicle can satisfy “operation.”
2. Intoxication – Either through a BAC of 0.08% or higher or through evidence of impairment by alcohol or drugs. This can be proven by Alcotest results, officer testimony, field sobriety tests, or toxicology.

Why This Matters: Understanding what the State must prove helps you and your attorney identify weak points. If prosecutors can’t establish both operation and intoxication beyond a reasonable doubt, the charge should not stand.

Related Resource: Learn what New Jersey prosecutors must prove to convict you of DWI.

39:4-50 – Statutory Inferences of Intoxication

Under N.J.S.A. 39:4-50, the law allows certain inferences, such as presuming intoxication if a driver’s BAC is .08% or higher or if they refuse to submit to testing.

New Jersey law allows certain inferences to simplify proof of intoxication:

• A BAC of .08% or higher is considered per se evidence of intoxication, even if the driver shows no outward signs (State v. Tischio).
• A driver’s refusal to provide a breath sample can be used to infer intoxication.
• In drug cases, courts may rely on toxicology reports or Drug Recognition Expert (DRE) evaluations to establish impairment.

Why This Matters: While these inferences give prosecutors powerful shortcuts, they are not absolute. Defense attorneys often challenge the reliability of BAC testing, the validity of DRE evaluations, or whether refusal warnings were correctly read.

39:4-50(a) – The 10-Year Step-Down Rule and How It Works

N.J.S.A. 39:4-50(a) provides a sentencing “step-down” for repeat offenders if more than 10 years have passed between DWI convictions, reducing penalties for later offenses.

New Jersey law recognizes that a single lapse in judgment many years ago should not always result in the same penalties as a more recent conviction. Under 39:4-50(a), the 10-Year Step-Down Rule allows a sentencing downgrade if enough time has passed between convictions.

Here’s how it works:

• If your second offense occurs more than 10 years after the first, the court may treat it as a first offense for sentencing.
• If your third offense occurs more than 10 years after the second, the court may treat it as a second offense.

In State v. Revie (2014), the New Jersey Supreme Court clarified that the step-down rule could apply more than once, giving repeat offenders an opportunity for reduced sentencing if they had long, offense-free intervals between DWIs.

There are limits, however. In State v. Ciancaglini, the court held that a prior refusal conviction does not count toward enhancing a DWI, and vice versa — refusal and DWI are separate statutes. CDL drivers are also subject to stricter federal disqualification rules that the step-down cannot reduce. Finally, under State v. Laurick, a defendant may avoid enhanced jail exposure if a prior conviction was uncounseled, even if the step-down doesn’t apply.

Why this matters: The difference between a third offense and a step-down to a “second offense” can mean 180 days in jail and an 8-year suspension versus 90 days in prison and a 1–2-year suspension.

Related Resources: Our 10-Year Step-Down Rule page provides full eligibility scenarios and Repeat DWI/DUI Penalties in New Jersey.

39:4-50.2 – Implied Consent to Breath Testing Explained

Under N.J.S.A. 39:4-50.2, every driver on New Jersey’s roads is deemed to have given implied consent to provide a breath sample if arrested for DWI. Refusing to give a sample is a separate offense with its own penalties under 39:4-50.4(a).

For a refusal charge to hold up, officers must follow precise rules:

• They must have probable cause to arrest you for DWI.
• They must read the Attorney General’s Standard Statement in full.
• You must be given two clear opportunities to provide the sample.

In State v. Marquez (2010), the NJ Supreme Court overturned a refusal conviction where the driver could not understand English, holding that the defendant must understand the Standard Statement. This case highlights how critical technical compliance is.

Drivers also have the right to arrange and pay for an independent test after providing breath samples. While police are not required to provide this, failure to honor a request can be used to challenge the reliability of the State’s case.

Why this matters: Many refusal charges succeed not because of what the driver said, but because of what they didn’t say — silence, hesitation, or giving conditional answers can all count as refusal.

Related Resources: Learn more in our New Jersey DWI Testing Guide, NJ Breath Test (Alcotest 7110), and Refusal Penalties.

39:4-50.2a – Implied Consent to Blood & Urine Testing

New Jersey law doesn’t limit implied consent to just breath samples. Under N.J.S.A. 39:4-50.2a, drivers arrested for DWI may also be required to provide blood or urine samples when alcohol or drugs are suspected.

Key Points

• Applies mainly in drug DUI cases, or when a medical condition prevents breath testing.
• Blood drawings must be done in a medically acceptable setting (usually hospital or clinic).
• Refusal to provide blood/urine can result in similar penalties to refusing a breath test.

Why This Matters
Drug-related DWIs rely heavily on toxicology. This statute helps defendants know their rights and limits when police request samples beyond the breathalyzer.

Related Resource: Learn about Blood & Urine Testing for DWI in New Jersey.

39:4-50.3 – Out-of-State DWI Convictions

N.J.S.A. 39:4-50.3 treats prior DWI convictions from other states as if they occurred in New Jersey for sentencing purposes.

This statute ensures out-of-state convictions count in New Jersey.

Key Points

• A prior DWI/DUI conviction in another state is treated as if it occurred in New Jersey.
• Applies even if the penalties in the other state were different.
• Used for calculating repeat-offense sentencing.

Why This Matters
Someone with an old DWI from New York, Pennsylvania, or elsewhere may face harsher penalties in NJ as a “second” or “third” offender, even if the prior state’s laws differ.

39:4-50.4(a) – Refusal to Submit to a Breath Test (Penalties & Defenses)

New Jersey law treats refusal to take a breath test as an offense, separate from the underlying DWI. Even if your DWI charge is dismissed, you can still be convicted of refusal under N.J.S.A. 39:4-50.4(a).

What Counts as Refusal?

Refusal goes beyond simply saying “no.” Courts have consistently ruled that:

• Remaining silent after the Standard Statement is read counts as refusal.
• Giving a conditional answer (“I’ll do it if my lawyer is present”) is a refusal.
• Providing weak or insufficient samples that prevent the machine from recording results is a refusal.
• Repeated delays or resistance, despite being warned, is refusal.

In State v. Widmaier, the court confirmed that conditional consent is still a refusal. In State v. Marquez, the court held that refusal convictions are invalid if the driver cannot understand the Standard Statement, highlighting the importance of language access.

Penalties for Refusal

Refusal penalties are mandatory and escalate with each offense:

• First offense: $300–$500 fine, 7–12-month license suspension, 6–12 months IID after suspension, IDRC attendance.
• Second offense: $500–$1,000 fine, 2-year suspension, 1–3 years IID.
• Third offense: $1,000 fine, 10-year suspension, 1–3 years IID.

On top of this, the Motor Vehicle Commission imposes a $1,000 annual surcharge for three years. Courts have clarified that if properly documented, voluntary early IID installation may provide credit toward suspension.

Why This Matters

Refusal convictions permanently mark your driving record, often resulting in insurance surcharges and disqualification from jobs requiring clean records. For CDL drivers, refusal can be career-ending even without a DWI conviction.

Related Resource: See our Refusal to Submit to a Breathalyzer page for a deeper look into penalties and defenses.

39:4-50.05 – Municipal Court Surcharge

Under N.J.S.A. 39:4-50.05, anyone convicted of DWI must pay an additional $100 municipal court surcharge.

This statute imposes a mandatory surcharge on anyone convicted of DWI in municipal court.

Key Points

• An extra $100 surcharge is added to fines and costs.
• Funds are earmarked for the Intoxicated Driver Resource Center (IDRC) program.

Why This Matters
Even minor surcharges add to the already steep financial burden of a DWI. Defendants should expect extra court fees beyond statutory fines.

39:4-50.08 – Intoxicated Driver Program Established

N.J.S.A. 39:4-50.08 creates the Intoxicated Driver Resource Center (IDRC), requiring mandatory education and offender evaluation.

This statute created the Intoxicated Driver Resource Center (IDRC) program.

Key Points

• Every person convicted of DWI or refusal must attend IDRC.
• IDRC provides education, evaluation, and treatment referrals.
• Duration depends on offense (usually 12–48 hours for first offenders).

Why This Matters
The IDRC is not optional. Failure to attend results in further suspension and possible jail. It’s a core part of New Jersey’s rehabilitation-first approach.

39:4-50.09 – IDRC Fees

N.J.S.A. 39:4-50.09 imposes mandatory program fees to cover IDRC costs, which vary depending on program length.

This section requires defendants to pay program fees.

Key Points

• Fees vary by length of program but are mandatory.
• Covers administration of classes, counseling, and monitoring.
• Nonpayment may result in extended license suspension.

Why This Matters
Many defendants are surprised by the hidden costs of IDRC. It’s more than a class — it’s an ongoing financial obligation.