Craters in London

The subject of how terrible London, Ontario roads are is certainly not new. Take the sinkhole in the downtown core, for example:

(http://www.atv.ca/images/shows-london-wingham-windsor/NEWSERPIC.jpg)

Unfortunately, the ultimate disrepair of London's streets doesn't stop with a single sinkhole. Craters, sinkholes, potholes, and the underground pathway to China are just the beginning of the problems all across the city. I personally have lost a tire to one of many craters, which in the end cost me my job (yes, I'm serious). The city, well aware of these problems, did little more than fill the holes with tar that sank again within a week. However, streets/roads that are not desperately in need of repair seem to find themselves constantly under construction. How on earth does this make any sense?

I think I'll go slam my head against the wall until the answer comes to me.