The guy's arguement kinda makes the point to me that with modern cars having much faster braking, acceleration and such (none of which make a close pass any safer) it should infact be easier with modern cars to get a nice wide overtake on the cyclist.
I think HC163 is more about stopping cars squeezing between cyclists and oncoming traffic than us actually needing that much space. The Audi overtake in the photo looks good but less than i thought the HC wanted, i wouldnt mind if it were a foot closer though. I find it varies with speed more than anything, an 80mph pass on a dual carriageway or 3 lane wide single is scarey as is the turbulance off lorries.
I dont think most of the silly narrow cycle lanes help either. The roads no wider but theyve basically just drawn lines on saying cyclists get to the kerb, drivers you can go full speed in your lane inches from the cyclists. Even on some videos of those new CS routes in London, they look plenty wide but then people ride two wide with some rather close to the traffic.