HSIS Variable Name

Name Interpretation

Variable sub Classification

Mean

Standard Deviation

Rd_char

The characteristics of the road section where the crash occurred

1―Straight

2―Upgrade

3―Downgrade

4―Horizontal curve

1.662

1.097

Rdsurf

The condition of the road surface where the crash occurred

1―Dry

2―Wet

3―Snow, muddy

2.396

0.831

Weather

Weather conditions when the crash occurred

1―Clear

2―Rain

3―Snow, sleet

4―Fog

1.533

0.803

Light

The type of light existed at the time of the crash

1―Daylight

2―Dark,Lights On

3―Dark, No Lights

1.642

0.69

Drv_age

The age of the driver of the vehicle involved

1―< 21 years

2―between 21 to 65

3―> 65 years

1.733

0.565

Drv_sex

Sex of the driver of the vehicle involved

1―Male

2―Female

1.401

0.49

Vehtype

Type or body of vehicle involved in the crash

1―Passenger Car

2―Van or Minivan

3―Bus

4―Truck

1.174

0.584

AADT

Annual Average Daily Traffic of the road section where the crash occurred

Numeric values in 1000s of vehicles.

Min. = 5.70

Max. = 27.618

13.027

5.499

Sec_leng

Section of the road where the crash occurred

Numeric values

Min. = 0.2 km

Max. = 0.9 km

0.518

0.204