Everyone who lives in or near Washington – as I did for five years – soon learns, to the yard, where the "front line" runs, where white people do not live, where their children do not go to school, and where to run a red light rather than linger.
In the city centre, the pavements, like the shops, offices and transport, can be minor fields of hostile racial encounters. Black America senses white condescension and entitlement a mile off.
In urban areas whites have increasingly arranged their lives so that – outside work – their paths rarely cross those of black Americans. Not only do they live in separate parts of town, they shop in separate malls and worship in separate churches. They use quite separate road systems, bypassing undesirable parts of town.
I once offered to share my taxi with an elderly (white) couple, if they were going the same way. It was at Baltimore airport, the queue was long; they were near the back and I was near the front. But no sooner were we in the cab, than the woman demanded an enormous detour to avoid the direct route into "white" north-west Washington through "black" north-east. The (black) driver was happy to go directly, the rest of the journey passed in frigid silence, punctuated by whispered racist remarks between the couple – about me.