Table 1.

FARS variables used to create three driving condition

Condition	Year	FARS Variable	Criteria for Inclusion	Reference Level
Seatbelt	1991–2006	Rest_use(1)	1=Shoulder Belt; 3=Lap & Shoulder Belt(2)	0=None Used/Not Applicable(3)
	1982–1990	Aut_rest(1)	1=Automatic Belt in Use	2=Automatic Belt Not in Use
Maneuvering	1982–2006	DR_CF1, DR_CF2, DR_CF3, or DR_CF4 (since 1997) (4)	26 to 37: (26 – Following Improperly; 27 - Improper or Erratic Lane Changing; 28 - Failure to Keep in Proper Lane or Running off Road; 28 - Failure to Keep in Proper Lane (since 2000); 29 - Illegal Driving on Road Shoulder, in Ditch, or Sidewalk, or on Median; 30 - Making Improper Entry to or Exit from Trafficway; 31 - Starting or Backing Improperly; 32 - Opening Vehicle Closure into Moving Traffic or Vehicle Is in Motion; 33 - Passing Where Prohibited by Posted Signs, Pavement Markings, Hill or Curve, or School Bus Displaying Warning Not to Pass; 34 - Passing on Wrong Side; 35 - Passing with Insufficient Distance or Inadequate Visibility or Failing to Yield to Overtaking Vehicle; 36 - Operating the Vehicle in an Erratic, Reckless, Careless or Negligent Manner or Operating at Erratic or Suddenly Changing Speeds)	0=None
			47 to 48 (47 - Making Right Turn from Left-Turn Lane or Making Left Turn from Right-Turn Lane; 48 - Making Improper Turn)
			52: (Operator Inexperience)
Speeding	1982–2006	DR_CF1, DR_CF2, DR_CF3, or DR_CF4 (since 1997)	44 (44 Driving too Fast for Conditions or in Excess of Posted Speed Limit)	0=None
			46 (Operating at Erratic or Suddenly Changing Speeds (until 1994))

⁽¹⁾Until 1990, safety belt use was recorded in variable aut_rest. From 1991 to 2006, variable rest_use was used to describe a larger variety of safety devices (e.g., including use of helmets or airbags).

⁽²⁾Safety levels used in this study are those (1) relevant to the sample (e.g., helmets and airbags are not included), and (2) those who clearly indicated a shoulder belt use (e.g., “Lap belt only,” “Type Unknown,” or “Used Improperly” levels were also excluded).

⁽³⁾Level 0 for variable Rest-use has been defined slightly differently over time: “None Used - Vehicle Occupant/Not Applicable - Nonmotorist” (1991–1993), “None Used - Vehicle Occupant; Not Applicable” (1994–2004), and “None Used/Not Applicable – Not a Motor Vehicle Occupant” (2005–2006).

⁽⁴⁾The “FARS variable” column indicates the FARS variables used to assign each driver to each “condition.” Each driver may have assigned up to four “driver conditions,” each indicated separately in variables DR_CF1 to DR_CF4 (if less than 4 conditions are needed, the remaining variables are set as missing). Depending on the crash conditions, FARS officials are supposed to select a condition number to indicate the proper condition. There is a myriad of such condition levels (up to 99). The column “criteria for inclusion” indicates the condition levels used to identify the conditions under study. The presence of any of these criteria levels in any of the four “driver condition” variables was used as to indicate the condition. The reference level was always “0,” indicating no special driver condition.