At what blood alcohol level do signs of intoxication start to become obvious?

• A. 50-100 mg%
• B. 100-150 mg%
• C. 150-200 mg%
• D. 200-250 mg%

Answer: (B)

As blood alcohol concentration (BAC) rises, coordination, judgment, and reaction time deteriorate. Signs of intoxication become clearly noticeable around a BAC of about 0.10% (100 mg/dL). The range of 100-150 mg% captures this level where impairment is obvious (slowed speech, unsteady balance, impaired decision-making). Lower ranges like 50-100 mg% tend to produce mild to moderate effects that may not be obviously intoxicated to everyone, while higher ranges (150-200 mg% or more) indicate more severe impairment and greater risk of dangerous outcomes. Note that mg% is the same as mg/dL, and many places consider legal intoxication around 0.08% (80 mg/dL), which falls within this 100-150 mg% window for noticeable impairment.