BD, carefully avoiding packed commuter trains, cycles into central London each day, mainly through the London Borough of Southwark. He continues to be astonished by the poor state of the roads, made even worse today by God who ordered some pretty horrid weather, as for some reason we had been a bit naughty over the weekend (maybe it was aimed at the Big Issue seller)

Anyway he is most interested whether Southwark Roads are worse than Lewisham, or Lambeth. Bromley roads do not count as they are all paved in gold. Although he had a motorcycle accident a few years ago as naughty Bromley wanted to save their pennies by not gritting to road during a very cold evening (unlike Lewisham).

BD - he weclomes all opinions

I understand from a recent article in ' Highways Today' that cyclists, due to putting relatively large amounts of weight on a relatively small surface area, cause ruts to appear in the roads in hot weather and this eventually destabilises the surface which eventually splits apart. Larger heavier vehicles spread their load a lot better.

Although thermal cracking, frost heaves, oxidation and vehicle damage all contribute to road deterioration a more common cause is the damage road maintenance causes to the bonding of the 'hogging'. The hogging is construction slang for the usually silica derived aggregate taking the 'live loads' (moving weight) pressure. When the bonding is disturbed it's structual integraty is undermined resulting in what is known as the 'bean bag effect'. Imagine a bag of frozen pea's and you sit on it, it will retain it's form but if you poke it with a stick areas of the frozen pea's bonding will start to give way or split the packet. Much like the shifting aggregate under the road splitting the Tarmac. A simple way of seeing this in action is by observing the road compared against the flow and direction of traffic. Heavy freight is usually heading into the capital on the left hand side resulting in more aggregate shifting over to the right causing more visible destruction often over a 10 to 20 year period. New Bitumen concrete based pavement is predicted to last about 30-40 years.
Lecture over but I'm a civil and demolitions engineer hoping to help.

Ahh so that explains why the road sags towards the pavement going South from Lambeth North, there was me thinking it was the buses!

I would say the roads in Southwark are pretty shocking. Wood Vale is sliding off in portions, once at the bottom of the Rye, nasty, then the High St bit before the library, don't get me started. And they filled in their canal; what kind of place let's their canal get filled in? At least they got some trees and a place to smoke weed (the spirit of Amsterdam lives on even though the canal has passed...).