In the mid-90s, Seattle started excavating its bus-stops-on-a-slope and pouring a new concrete foundation, because the busses were warping the asphalt so badly.

I was just back there this last weekend, and you can no longer see any of the concrete - it has all been coated with asphalt. However, I assume its a rather thin layer because none of the bus stops I checked show the signs of damage that were becoming common in 90-96.