[spgv]

1.They are cheaper to install and maintain (in short term).
2.Longivity is not as much as concrete road so some of the cheap maintenance cost is offset.
3.Repairing is fast and easy as the contractors would only replace damaged blocks, unlike a tar road which requires extensive setup to repair properly.
4.Safety, its cheap at the cost of safety.
Advantage
1.Its repair friendly and usefull for road areas prone to frequent damage like the ones near watersupply, sewers manholes more of such stuff u can imagine.
2.The strip is used(or in future) for laying of other utilities like cables for street light or power distribution, water or drain lines below.

I personally donot like this stuff on roads. Good for paved areas around residential, commercial buildings, footpath and in parks. I have seen special design on walkways that have openings to allow rain water percolation.

[VijayAnand1]

The interlocking pavement or cobblestone pavements are a disaster to bikers and alike. This is great as long as moss does not cover the upper portion of the blocks. In humid conditions and hilly terrains, the chances of them moss-ing up are an extremely high probability and I myself have had many close calls at speeds less than 10 KMPH enough to give me a heart attack.

There is something about these moss ridden and or curvatured moss ridden surfaces, their tendency to slip both people are tires are extremely unnatural and total unsuspecting. I always make sure I heed double, triple caution when riding over such pavements, if I happen to.

Cheers!
VJ

[Yieldway17]

These are dangerous as sand and water when they eventually settle on top of them become a dangerous combination and makes it slippery for two wheelers. I have seen them in couple of roads in a town near me and they always have less traction than the adjoining tar surface and I'm extra cautions traversing them. Any sudden braking activity has almost near 100% chance of one ending up on the road.