An Alternative Method for Traffic Accident Severity Prediction: Using Deep Forests Algorithm

Table 1

Categorization criteria of several features.

Light conditions	Description	Weather conditions	Description	Road surface conditions	Description
1	Daylight: street lights present	1	Fine without high winds	1	Dry
2	Daylight: no street lighting	2	Raining without high winds	2	Wet/damp
3	Daylight: street lighting unknown	3	Snowing without high winds	3	Snow
4	Darkness: street lights present and lit	4	Fine with high winds	4	Frost/ice
5	Darkness: street lights present but unlit	5	Raining with high winds	5	Unknown
6	Darkness: no street lighting	6	Snowing with high winds
7	Darkness: street lighting unknown	7	Fog or mist
		8	Other
		9	Unknown