Driving After Drug or Alcohol Use

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APPENDIX B:   STANDARD ERROR TABLES

As stated earlier, this report presents results of tests of statistical significance for comparisons of prevalence estimates. Differences were tested for statistical significance using Z tests. The Z test takes into account the sizes of the subsamples being compared and the degree of variation among sample members. Statistical significance refers to the probability that a difference as large as that observed would occur due to random error in the estimates if there were no difference in the prevalence rates in the groups being compared. Unless otherwise noted, differences discussed in the text were statistically significant at the .05 level or lower. That is, a sample difference equal to or larger than the observed sample difference is likely to occur fewer than 5 times in 100 by chance alone (.05 level). Analogous definitions apply to significance at the .01 and .001 levels.

Standard errors of the estimates are not presented in the main text of this report. However, this appendix contains standard errors for the estimates presented in this report. These standard errors were calculated using SUDAAN [ See Shah, B.V., Barnwell, B.G., Hunt, P.N., & LaVange, L.M. (1994). SUDAAN user ’s manual: Release 6.4 . Research Triangle Park, NC: Research Triangle Institute.] . The reader may use these standard errors to perform additional hypothesis testing. The difference in prevalence rates may be determined using the standard difference in percentages test expressed as

where p₁ is the estimated percentage of the first subgroup (e.g., the estimated percentage of males who drove within two hours of drug use in the past year), p₂ is the corresponding estimate of the second group (e.g., females), SE(p₁) is the standard error of p₁, and SE(p₂) is the standard error of p₂. So, using our example, as shown in Table 3a., 6.8 percent of males reported driving within two hours of drug use in the past year and 3.8 percent of females reported the same behavior. As shown in Table SE3a., the standard errors for these estimates are 0.47 and 0.32, respectively. Therefore, using the above equation it follows that Z = 5.28, which is greater than the critical value of 1.96. Therefore, the difference in the two percentages is significant at the .05 level; in fact, it is significant at the .001 level.

The standard error tables are numbered to correspond with the detailed data tables. For example the standard errors for Table 2 are found in Table SE2.

TABLE SE2.Percentage of Drivers Age 16+ in Age, Gender, and Regional Groups who Drove Within Two Hours of Substance Use by Substance Used, STANDARD ERRORS, 1996

	Drove within Two Hours of Substance Use
Demographic Characteristic	After Alcohol Use	After Marijuana Use	After Other Drug Use1
TOTAL	0.92	0.22	0.21
AGE
16-20 Yrs	1.42	1.03	0.48
21-34 Yrs	1.34	0.36	0.31
35+ Yrs	1.13	0.27	0.29
GENDER
Male	1.46	0.37	0.32
Female	0.76	0.18	0.28
REGION
Northeast	1.73	0.47	0.37
North Central	2.46	0.51	0.25
South	1.46	0.36	0.44
West	1.95	0.60	0.51

Note:  This table is restricted to people who drove a car or other motor vehicle in the past year.

¹Includes cocaine, and the medical and non-medical use of tranquilizers, stimulants, and sedatives.

Office of Applied Studies, SAMHSA, National Household Survey on Drug Abuse, 1996.

TABLE SE3a.Percentage of Drivers 16+ within Age, Gender, Racial/Ethnic, and Regional Groups Age who Drove within Two Hours of Substance Use in the Past Year by Substance Used, STANDARD ERRORS, 1996

				Drove within Two Hours of Substance Use
Demographic Characteristic		Non-Impaired Driver1		After Alcohol Use Only (No Drugs)	After Drug Use2 (With or Without Alcohol)
TOTAL		0.97		0.94	0.28
AGE
16-18 Yrs		1.38		1.03	1.05
19-20 Yrs		2.71		2.10	1.89
21-25 Yrs		2.11		1.96	0.80
26-34 Yrs		1.27		1.09	0.46
35-49 Yrs		1.54		1.32	0.73
50+ Yrs		1.85		1.79	0.44
GENDER
Male		1.52		1.48	0.47
Female		0.81		0.77	0.32
RACE/ETHNICITY
White (Non-Hispanic)		1.19		1.18	0.34
Black (Non-Hispanic)		1.14		0.96	0.53
Hispanic		1.19		1.10	0.44
Other		2.78		2.22	1.57
REGION
Northeast		1.91		1.90	0.51
North Central		2.42		2.29	0.54
South		1.53		1.53	0.57
West		2.17		1.78	0.66

Note:This table is restricted to people who drove a car or other motor vehicle in the past year.

¹"Non-impaired" drivers are those respondents who drove a motor vehicle in the 12 months prior to the NHSDA interview, but reported that they did not drive within two hours after using drugs and/or alcohol during that same period.

²Includes marijuana, cocaine, and the medical and non-medical use of tranquilizers, stimulants, and sedatives.

Office of Applied Studies, SAMHSA, National Household Survey on Drug Abuse, 1996.

TABLE SE3b.Percentage of Drivers Age 16+ within Marital, Educational, Employment, and Personal Income Groups who Drove within Two Hours of Substance Use in the Past Year by Substance Used, STANDARD ERRORS, 1996

				Drove within Two Hours of Substance Use
Demographic Characteristic		Non-Impaired Driver1		After Alcohol Use Only (No Drugs)	After Drug Use2 (With or Without Alcohol)
TOTAL		0.97		0.94	0.28
MARITAL STATUS
Married		1.15		1.17	0.35
Div./Sep./Wid.		1.95		1.72	0.78
Never Married		1.31		1.22	0.67
EDUCATION
<High School		1.82		1.37	1.01
High School Grad		1.35		1.16	0.57
Some College		1.73		1.67	0.59
College Grad		1.87		1.87	0.54
EMPLOYMENT STATUS
Full-Time		1.23		1.18	0.38
Part-Time		1.77		1.66	0.97
Unemployed		3.22		3.31	1.72
Not in Work Force3		1.93		1.82	0.44
PERSONAL INCOME
<$10,000		1.12		0.92	0.61
$10,000 - $19,999		1.46		1.35	0.51
$20,000 - $39,999		1.56		1.54	0.58
$40,000 - $49,999		3.17		2.85	1.25
$50,000 - $74,999		3.55		3.45	0.70
$75,000+		5.26		5.29	2.09

Note:  This table is restricted to people who drove a car or other motor vehicle in the past year.

¹"Non-impaired" drivers are those respondents who drove a motor vehicle in the 12 months prior to the NHSDA interview, but reported that they did not drive within two hours after using drugs and/or alcohol during that same period.

²Includes marijuana, cocaine, and the medical and non-medical use of tranquilizers, stimulants, and sedatives.

³Includes full-time homemakers, non-working students, the retired, and the disabled.

Office of Applied Studies, SAMHSA, National Household Survey on Drug Abuse, 1996.

TABLE SE4.Percentage of Drivers Age 16+ within Age by Gender, Racial/Ethnic by Age, and Racial/Ethnic by Gender Groups who Drove within Two Hours of Substance Use in the Past Year by Substance Used, STANDARD ERRORS, 1996

				Drove within Two Hours of Substance Use
Demographic Characteristic		Non-Impaired Driver1		After Alcohol Use Only (No Drugs)	After Drug Use2 (With or Without Alcohol)
TOTAL		0.97		0.94	0.28
AGE BY GENDER
16-20 Years
Male		2.15		1.68	1.44
Female		1.82		1.22	1.33
21+ Years
Male		1.64		1.63	0.51
Female		0.83		0.79	0.34
RACE/ETHNICITY BY AGE
White (Non-Hispanic)
16-20 Years		2.00		1.45	1.31
21+ Years		1.23		1.24	0.35
Black (Non-Hispanic)
16-20 Years		2.15		1.58	1.86
21+ Years		1.23		1.05	0.55
Hispanic
16-20 Years		2.11		1.60	1.49
21+ Years		1.38		1.27	0.49
RACE/ETHNICITY BY GENDER
White (Non-Hispanic)
Male		1.87		1.85	0.57
Female		0.98		0.94	0.39
Black (Non-Hispanic)
Male		1.88		1.72	0.80
Female		1.21		0.88	0.74
Hispanic
Male		1.60		1.44	0.69
Female		1.27		1.24	0.74

Note:  This table is restricted to people who drove a car or other motor vehicle in the past year.

¹"Non-impaired" drivers are those respondents who drove a motor vehicle in the 12 months prior to the NHSDA interview, but reported that they did not drive within two hours after using drugs and/or alcohol during that same period.

²Includes marijuana, cocaine, and the medical and non-medical use of tranquilizers, stimulants, and sedatives.

Office of Applied Studies, SAMHSA, National Household Survey on Drug Abuse, 1996.

TABLE SE5.Percentage of Drivers Age 16+ Arrested and Not Arrested and on Probation and Not on Probation in the Past Year who Drove within Two Hours of Substance Use in the Past Year by Substance Used, STANDARD ERRORS, 1996

				Drove within Two Hours of Substance Use
During the Past Year		Non-Impaired Driver1		After Alcohol Use Only (No Drugs)	After Drug Use2 (With or Without Alcohol)
TOTAL		0.97		0.95	0.29
ARRESTED (FOR ANY REASON)
Yes		2.67		2.37	1.62
No		1.01		0.98	0.28
ON PROBATION (FOR ANY REASON)
Yes		5.36		3.32	4.09
No		1.00		0.97	0.27

Note: This table is restricted to people who drove a car or other motor vehicle in the past year.

¹"Non-impaired" drivers are those respondents who drove a motor vehicle in the 12 months prior to the NHSDA interview, but reported that they did not drive within two hours after using drugs and/or alcohol during that same period.

² Includes marijuana, cocaine, and the medical and non-medical use of tranquilizers, stimulants, and sedatives.

Office of Applied Studies, SAMHSA, National Household Survey on Drug Abuse, 1996.

TABLE SE6a.Age, Gender, Racial/Ethnic, and Regional Distribution of Drivers Age 16+ who Drove within Two Hours of Substance Use in the Past Year by Substance Used, 1996

			Drove within Two Hours of Substance Use
Demographic Characteristic	Non-Impaired Driver1		After Alcohol Use Only (No Drugs)	After Drug Use2 (With or Without Alcohol)
TOTAL	0.97		0.94	0.28
AGE
16-18 Yrs	0.22		0.26	1.01
19-20 Yrs	0.18		0.32	1.29
21-25 Yrs	0.44		0.73	1.38
26-34 Yrs	0.58		1.14	1.89
35-49 Yrs	1.06		1.66	3.24
50+ Yrs	1.46		2.18	2.59
GENDER
Male	1.22		1.22	2.56
Female	1.22		1.22	2.56
RACE/ETHNICITY
White (Non-Hispanic)	1.20		0.85	1.99
Black (Non-Hispanic)	0.76		0.55	0.98
Hispanic	0.46		0.49	0.73
Other	0.69		0.36	1.21
REGION
Northeast	1.51		1.94	2.40
North Central	1.82		2.67	3.12
South	1.50		2.37	3.14
West	1.49		1.67	2.88

Note:This table is restricted to people who drove a car or other motor vehicle in the past year.

¹"Non-impaired" drivers are those respondents who drove a motor vehicle in the 12 months prior to the NHSDA interview, but reported that they did not drive within two hours after using drugs and/or alcohol during that same period.

²Includes marijuana, cocaine, and the medical and non-medical use of tranquilizers, stimulants, and sedatives.

Office of Applied Studies, SAMHSA, National Household Survey on Drug Abuse, 1996.

TABLE SE6b.Marital, Educational, Employment, and Personal Income Distribution of Drivers Age 16+ who Drove within Two Hours of Substance Use in the Past Year by Substance Used, STANDARD ERRORS, 1996

			Drove within Two Hours of Substance Use
Demographic Characteristic	Non-Impaired Driver1		After Alcohol Use Only (No Drugs)	After Drug Use2 (With or Without Alcohol)
TOTAL	0.97		0.94	0.28
MARITAL STATUS
Married	1.00		1.64	3.26
Div./Sep./Wid.	0.62		1.25	2.20
Never Married	0.75		1.18	2.98
EDUCATION
<High School	1.14		0.90	2.78
High School Grad	1.30		1.65	3.09
Some College	1.04		1.57	2.18
College Grad	1.23		2.02	2.70
EMPLOYMENT STATUS
Full-Time	1.28		2.17	2.65
Part-Time Only	0.70		1.06	2.17
Unemployed	0.29		0.59	1.14
Not in Work Force3	1.18		2.00	2.11
PERSONAL INCOME
<$10,000	1.17		0.96	2.82
$10,000 - $19,999	0.87		1.35	2.06
$20,000 - $39,999	1.07		1.82	2.79
$40,000 - $49,999	0.42		0.91	1.61
$50,000 - $74,999	0.53		1.20	0.92
$75,000+	0.35		1.52	1.46

Note:  This table is restricted to people who drove a car or other motor vehicle in the past year.

¹"Non-impaired" drivers are those respondents who drove a motor vehicle in the 12 months prior to the NHSDA interview, but reported that they did not drive within two hours after using drugs and/or alcohol during that same period.

²Includes marijuana, cocaine, and the medical and non-medical use of tranquilizers, stimulants, and sedatives.

³Includes full-time homemakers, non-working students, the retired, and the disabled.

Office of Applied Studies, SAMHSA, National Household Survey on Drug Abuse, 1996.

TABLE SE7.Age by Gender, Racial/Ethnic by Age, and Racial/Ethnic by Gender Distribution of Drivers Age 16+ who Drove within Two Hours of Substance Use in the Past Year by Substance Used, STANDARD ERRORS, 1996

			Drove within Two Hours of Substance Use
Demographic Characteristic	Non-Impaired Driver1		After Alcohol Use Only (No Drugs)	After Drug Use2 (With or Without Alcohol)
TOTAL	0.97		0.94	0.28
AGE BY GENDER
16-20 Years
Male	1.52		4.56	3.85
Female	1.52		4.56	3.85
21+ Years
Male	1.35		1.24	3.22
Female	1.35		1.24	3.22
RACE /ETHNICITY BY AGE
White (Non-Hispanic)
16-20 Years	0.40		0.48	1.98
21+ Years	0.40		0.48	1.98
Black (Non-Hispanic)
16-20 Years	0.66		1.27	4.07
21+ Years	0.66		1.27	4.07
Hispanic
16-20 Years	0.75		1.36	4.57
21+ Years	0.75		1.36	4.57
RACE/ETHNICITY BY GENDER
White (Non-Hispanic)
Male	1.47		1.31	2.89
Female	1.47		1.31	2.89
Black (Non-Hispanic)
Male	1.97		2.73	5.48
Female	1.97		2.73	5.48
Hispanic
Male	1.73		2.52	6.59
Female	1.73		2.52	6.59

Note:  This table is restricted to people who drove a car or other motor vehicle in the past year.

¹"Non-impaired" drivers are those respondents who drove a motor vehicle in the 12 months prior to the NHSDA interview, but reported that they did not drive within two hours after using drugs and/or alcohol during that same period.

²Includes marijuana, cocaine, and the medical and non-medical use of tranquilizers, stimulants, and sedatives.

Office of Applied Studies, SAMHSA, National Household Survey on Drug Abuse, 1996.

TABLE SE8.Past-Year Arrest and Probation Status Distribution of Drivers Age 16+ Arrested who Drove within Two Hours of Substance Use in the Past Year by Substance Used, STANDARD ERRORS, 1996

	Drove within Two Hours of Substance Use
During the Past Year	Non-Impaired Driver1	After Alcohol Use Only (No Drugs)	After Drug Use2 (With or Without Alcohol)
TOTAL	0.97	0.95	0.29
ARRESTED (FOR ANY REASON)
Yes	0.58	1.11	2.86
No	0.58	1.11	2.86
ON PROBATION (FOR ANY REASON)
Yes	0.22	0.22	1.30
No	0.22	0.22	1.30

Note:  This table is restricted to people who drove a car or other motor vehicle in the past year.

¹"Non-impaired" drivers are those respondents who drove a motor vehicle in the 12 months prior to the NHSDA interview, but reported that they did not drive within two hours after using drugs and/or alcohol during that same period.

²Includes marijuana, cocaine, and the medical and non-medical use of tranquilizers, stimulants, and sedatives.

Office of Applied Studies, SAMHSA, National Household Survey on Drug Abuse, 1996.

TABLE SE9.Distribution of Size of Road Driven, Area Driven, Day of Week Driven, and Time of Day Driving Began on Most Recent Occasion of Driving within Two Hours of Marijuana Use for Drivers Age 16+ who Drove Following Marijuana Use in the Past Year by Age Group, STANDARD ERRORS, 1996

Driving Patterns	TOTAL	16-20 Years	21+ Years
SIZE OF ROAD
Interstate/Highway/Freeway	2.85	3.77	3.43
Only on Smaller Roads	2.85	3.77	3.43
AREA
Rural (open country)	2.96	3.36	3.44
Urban (city or town)	2.99	4.25	3.48
Suburban (town just outside of a large city)	2.30	2.57	3.14
DAY OF WEEK
Weekday1	3.01	4.28	3.70
Weekend2	3.01	4.28	3.70
TIME OF DAY BEGAN
12:00 a.m. to 5:59 a.m.	2.20	4.22	2.15
6:00 a.m. to 11:59 a.m.	1.44	2.33	1.66
12:00 p.m. to 5:59 p.m.	3.16	3.09	3.83
6:00 p.m. to 11:59 p.m.	2.92	3.64	3.78

Note:  This table is restricted to people who drove a car or other motor vehicle in the past year.

¹Monday, Tuesday, Wednesday, or Thursday.

²Friday, Saturday, or Sunday.

Office of Applied Studies, SAMHSA, National Household Survey on Drug Abuse, 1996.

TABLE SE10.Distribution of Starting Point and Destination on Most Recent Occasion of Driving within Two Hours of Marijuana Use for Drivers Age 16+ who Drove Following Marijuana Use in the Past Year by Age Group, STANDARD ERRORS, 1996

Starting Point and Destination	TOTAL	16-20 Years	21+ Years
STARTING POINT
Home	3.61	3.68	4.40
Friend/Relative’s Home	3.74	4.70	4.44
Public Location1	2.36	3.31	3.22
DESTINATION
Home	3.01	5.28	3.66
Friend/Relative’s Home	1.87	3.35	2.16
Public Location1	3.19	4.45	3.95

Note:  This table is restricted to people who drove a car or other motor vehicle in the past year.

¹Includes bar or nightclub, restaurant, sporting event, concert, workplace, no place in particular, or unspecified.

Office of Applied Studies, SAMHSA, National Household Survey on Drug Abuse, 1996.

TABLE SE11.Percentage of Drivers Age 16+ who Drove within Two Hours of Marijuana Use in the Past Year Reporting Reasons for Driving on Most Recent Occasion of Driving Following Marijuana Use by Age Group, STANDARD ERRORS, 1996

Reported Reason for Driving	16-20 Years	21+ Years
No other way to get there	3.42	4.08
Not high enough to cause a crash	5.52	4.47
Police not likely to catch me	3.65	4.42
No one else available to drive	4.50	4.41
Had an appointment or curfew	3.99	3.08
Other reason	3.76	4.17

Note:  This table restricted to people who drove a car or other motor vehicle in the past year. Responses do not sum to 100% because respondents could mark more than one answer.

Office of Applied Studies, SAMHSA, National Household Survey on Drug Abuse, 1996.

TABLE SE12.Distribution of Perceived Extent to which Marijuana Affected Ability to Drive Safely on Most Recent Occasion of Driving within Two Hours of Marijuana Use for Drivers Age 16+ who Drove Following Marijuana Use in the Past Year by Age Group, STANDARD ERRORS, 1996

		Amount Marijuana Affected Ability to Drive Safely
		A Lot/A Little	Not at All
TOTAL		2.59	2.59
16-20 Years		5.37	5.37
21+ Years		3.46	3.46

Note:  This table is restricted to people who drove a car or other motor vehicle in the past year.

Office of Applied Studies, SAMHSA, National Household Survey on Drug Abuse, 1996.

TABLE SE13.Distribution of Perceived Likelihood of Being Stopped by the Police when Driving Following Marijuana Use Compared to when Driving on Other Occasions for Drivers Age 16+ who Drove within Two Hours of Marijuana Use in the Past Year by Age Group, STANDARD ERRORS, 1996

		How Likely Stopped by Police If Use Marijuana and Drive
		A Lot/A Little More Likely	No More Likely
TOTAL		2.68	2.68
16-20 Years		4.93	4.93
21+ Years		3.11	3.11

Note:  This table is restricted to people who drove a car or other motor vehicle in the past year.

Office of Applied Studies, SAMHSA, National Household Survey on Drug Abuse, 1996.

TABLE SE14.Distribution of Number of Days in Past Month Drove within Two Hours of Alcohol or Marijuana Use, for All Ages and within Age Groups, for Drivers Age 16+ who Drove Following Alcohol Use Only or Marijuana Use in the Past Year by Substance Type, STANDARD ERRORS, 1996

Number of Days	Alcohol	Marijuana
TOTAL
None	1.57	3.43
1-5 Days	1.66	3.56
6+ Days	0.70	2.22
16-20 YEARS
None	4.46	3.68
1-5 Days	4.30	4.82
6+ Days	2.57	3.79
21+ YEARS
None	1.62	4.10
1-5 Days	1.72	4.35
6+ Days	0.73	2.90

Note:  This table is restricted to people who drove a car or other motor vehicle in the past year.

Office of Applied Studies, SAMHSA, National Household Survey on Drug Abuse, 1996.

TABLE SE15.Distribution of Level of Past-Month Alcohol Use or Past-Year Marijuana Use for Drivers Age 16+ who Drove within Two Hours of Alcohol Use Only or Marijuana Use in the Past Year by Age Group, STANDARD ERRORS, 1996

	ALCOHOL		MARIJUANA2
	Heavy Use	Medium/Low Use	Heavy Use	Medium/Low Use
TOTAL	0.96	0.96	3.16	3.16
16-20 Years	4.34	4.34	4.39	4.39
21+ Years	0.99	0.99	3.91	3.91

Note:  This table is restricted to people who drove a car or other motor vehicle in the past year.

¹Heavy = Had at least five drinks on at least five occasions in the past 30 days; Medium = Had at least five drinks on at least one, but no more than four occasions during the past 30 days (i.e., binge drinking); Low = Used alcohol, but had at least one, but no more than four drinks on any occasion during the past 30 days.

²Heavy = Used weekly; Medium = Used monthly, but not weekly; Low = Used in past year, but not weekly or monthly.

Office of Applied Studies, SAMHSA, National Household Survey on Drug Abuse, 1996.

TABLE SE16.Distribution of Whether or Not Other Substances Were Also Used on Most Recent Occasion of Driving within Two Hours of Marijuana Use for Drivers Age 16+ who Drove Following Marijuana Use in the Past Year by Age Group, STANDARD ERRORS, 1996

	Alone	With Alcohol	With Other Drug
TOTAL	2.80	2.83	0.88
16-20 Years	3.98	3.73	1.63
21+ Years	3.49	3.49	1.07

Note:This table is restricted to people who drove a car or other motor vehicle in the past year.

Office of Applied Studies, SAMHSA, National Household Survey on Drug Abuse, 1996.

TABLE SE17.Percentage of Drivers Age 16+ who Drove within Two Hours of Using Marijuana and Another Substance in the Past Year by Age Group, STANDARD ERRORS, 1996

Drove after Using Marijuana and...	16-20 Years	21+ Years
Alcohol	3.93	2.91
Any Other Drug1	3.87	3.02

Note:  This table is restricted to people who drove a car or other motor vehicle in the past year. Responses do not sum to 100% because respondents can fall into more than one category.

¹Includes cocaine, heroin, hallucinogens, inhalants, and the medical and non-medical use of tranquilizers, analgesics, stimulants, and sedatives.

Office of Applied Studies, SAMHSA, National Household Survey on Drug Abuse, 1996.

TABLE SE18.Distribution of Number of Drinks Consumed, Number of Hours between First and Last Drink, and Time between Last Drink and when Driving Began on Most Recent Occasion of Driving within Two Hours of Alcohol Use for Drivers Age 16+ who Drove Following Alcohol Use in the Past Year by Age Group, STANDARD ERRORS, 1996

	TOTAL	16-20 Years	21+ Years
NUMBER OF DRINKS
1-2 Drinks	1.69	4.27	1.74
3-4 Drinks	1.74	3.58	1.84
5+ Drinks	1.18	3.93	1.21
HOURS BETWEEN FIRST AND LAST DRINK
4+ Hours	1.36	3.95	1.42
2-4 Hours	1.77	3.45	1.92
1-2 Hours	1.80	3.04	1.92
<1 Hour	1.41	4.24	1.49
Only Had 1 Drink	1.42	1.28	1.49
TIME BETWEEN LAST DRINK AND WHEN DRIVING BEGAN
1-2 Hours	1.75	3.80	1.88
<1 Hour	1.75	3.80	1.88

Note:  This table is restricted to people who drove a car or other motor vehicle in the past year.

Office of Applied Studies, SAMHSA, National Household Survey on Drug Abuse, 1996.

TABLE SE19.Distribution of Estimated Blood Alcohol Concentration (BAC) Levels¹ on Most Recent Occasion of Driving within Two Hours of Alcohol Use for Drivers Age 16+ who Drove Following Alcohol Use in the Past Year by Age within Gender, STANDARD ERRORS, 1996

		Males			Females
BAC Level	TOTAL	Total	16-20 Years	21+ Years	Total	16-20 Years	21+ Years
<.02	1.74	2.22	4.62	2.28	2.84	6.55	3.06
.02-.079	1.73	1.97	5.74	2.04	3.17	7.28	3.35
.08+	0.67	0.80	4.91	0.76	1.28	7.74	1.27

Note:  This table is restricted to people who drove a car or other motor vehicle in the past year.

¹See Appendix D for method used to estimate BAC levels. BAC levels are reported in grams per deciliter.

Office of Applied Studies, SAMHSA, National Household Survey on Drug Abuse, 1996.

TABLE SE20.Average Estimated Blood Alcohol Concentration (BAC) Level¹ on Most Recent Occasion of Driving within Two Hours of Alcohol Use for Drivers Age 16+ who Drove Following Alcohol Use in the Past Year by Gender and Age, STANDARD ERRORS, 1996

		Gender
Age	TOTAL	Males	Females
TOTAL	0.001	0.002	0.002
16-20 YRS	0.011	0.013	0.023
21-25 YRS	0.003	0.004	0.005
26-34 YRS	0.002	0.002	0.004
35-49 YRS	0.002	0.002	0.004
50+ YRS	0.002	0.002	0.005

Note:  This table is restricted to people who drove a car or other motor vehicle in the past year.

¹See Appendix D for method used to estimate BAC levels. BAC levels are reported in grams per deciliter.

Office of Applied Studies, SAMHSA, National Household Survey on Drug Abuse, 1996.

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This page was last updated on June 16, 2008.

SAMHSA, an agency in the Department of Health and Human Services, is the Federal Government's lead agency for improving the quality and availability of substance abuse prevention, addiction treatment, and mental health services in the United States.