In all developed countries, a motorcycle should be given and usually has the same amount of space on the road as a car would have. This is the law. Because this is practiced, there really isn't a need for motorcyclists there to "split-lanes".
In SG however.. many drivers (taxi drivers especially) see a motorcycle on the lane next to him as a chance to change lanes. Because our bikes are smaller than the cars, it somehow justifies them squeezing into our lane and forcing us to to the edge of our lane.. which leads to us splitting-lanes anyway.
Then again if all motorcyclists in Singapore