Driving tests

I experienced Cairo traffic for the first time this week from a relatively safe place, the passenger seats in taxis. The roads are just chunks of tarmac used for vehicles that are generally heading in the same direction, the best comparison I could think of would be a jumble of different size ball bearings rolling along a drainpipe. There were some lane markings they weren't taking any significant part in the proceedings. Tooting of horns and flashing of headlights played a large role, mainly as communication rather than aggression, but I failed to see the point of a "Let me through" communication when the traffic was clearly stationery on all tarmac spaces as far as the eye could see.