I've got to say that situation would have me scared, regardless of whether I could identify the colour or anything else about the driver (and I'm in the UK). A woman is aware of how vulnerable she is - and a woman with small children doubly so. I know that once I had a baby, my potential danger radar seriously spiked.

That said, that's all general and hypothetical. In the particular situation reported here, it's certainly possible that the white woman was being racist in her reactions to her Black neighbour, but only the woman and her conscience will know that for certain.