When I get into a situation where I need to brake suddenly (the typical freeway scenario), I initially brake HARDER than necessary, to ensure that the driver behind me takes note (in most situations there is sufficient time for all the cars to stop safely, but some bonehead just doesn't realise how much the cars in front are slowing). This normally buys me some space in front, I can ease of the brakes, and give bozo behind me some space as well. If I realise that things aren't looking too good behind me, I also have a few extra moments to take evasive action.
This practice has saved my butt on numerous occassions in the past - driving in South Africa is not for the feint-hearted.
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2008 Alpine White 135iM, High gloss black / satin chrome trim, Xenon lights, Hi-Fi sound, ext. lighting package, BMW Performance wheels, side skirts, pedals, gear knob, exhaust, high gloss black grills, carbon mirrors, carbon decklid spoiler, 35% security laminate, Tii graphics