The Woman in The Road

Key sections concerning 'the woman'

p.17: From daydreams on the road there was no waking .... Freeze this frame. Now call down your dark and your cold and be damned. 
p.54: The clocks stopped at 1:17. ... What is happening?p.56: He thought about the picture in the road ... You mean you wish that you were dead. 
p.57: What in God’s name are you talking about? We’re not survivors. We’re the walking dead in a horror film ... The one thing I can tell you is that you wont survive for yourself. 
p.60: She was gone and the coldness of it was her final gift ... wrapped his son in a towel.

Possible interpretations of the woman

The man and the woman represent different ways humans react to a apocalyptic situation

The mans first instinct was to survive. E.g. filling the bath tub.

The woman on the other hand goes straight to self-destruction. She also attempts to take the man and the boy with her. "when there were three bullets".

She represents both the giving and taking of life

Carries a baby after the apocalypse. She's described as "Cradling her belly" when the catastrophe fist strikes.
But after the boy is born she abandons him and commits suicide. "she was gone and the cold was her last gift".

McCarthy needs someone who is no longer present to represent life as it used to be

The reminders of a past life helps create a sense of loneliness for the man and the boy especially when the man dies and all ties to the past world are severed.
It also shows the mans desperation to hold on to his past life through flashbacks and dreams of his now dead wife.