Foundry Traffic Lights

And far less dangerous. Riding slow encourages motorists to see you as a problem that needs to be dealt with. Riding fast in the centre of the road gives motorists less of an opportunity to take liberties with you

Speed is good if you have it, but it is perfectly possible to ride assertively very slowly. Just look at all those people in Notting Hill on black bikes with wicker baskets. If you have the confidence, you will display that on the bike. You don't even have to be posh to project that.