Since it opened in 1999, Bangkok's elevated Skytrain has provided a lofty perspective on a horribly congested city. Compared to ground level, where towers of concrete block out the light, the view from above is almost tranquil, as oases of greenery peek out from the urban sprawl. This vision normally ends when you leave the station and descend to the maelstrom of street life, dodging the food stalls, beggars and confused tourists with their dog-eared maps. Diesel fumes waft from the passing traffic, and the temperature soars as you pass yet another vat of burning oil in full-on frying mode. It's a far cry from the air-conditioned Skytrain. But these days, there's an alternative. The Skytrain has spawned a spin-off: the Skywalk. As the name suggests, it's a fancy, well-lit, elevated walkway that links stations to other buildings, typically a hotel or shopping mall. Some luxury condominiums boast their own Skywalk access. One Skywalk runs all the way from Chitlom station to Siam, the next stop, linking the shopping malls along the route. So you can cover the entire stretch without ever touching the ground or mingling with the hoi polloi. My local station has been in a state of chaos in recent months as it rolls out its own Skywalk, which will eventually whisk passengers to nearby hotels and malls. It has turned into something of an engineering conundrum to link the walkway to the station, which wasn't designed with much room to spare. Any urban planner worth his salt could explain how modes of transport change patterns of human behaviour. The Skytrain, and the subway line that opened in 2004, have clearly had an impact on how people get around town, and businesses have taken note. Every drinks vendor wants to be near the station exit, where thirsty commuters pass by. For retailers located on major roads beneath the Skytrain, the effects aren't always so positive. Last week, a friend reported that some upscale furniture stores on bustling Sukhumvit Road appeared to be going out of business. The reason, he surmised, was that well-off shoppers take the Skytrain rather than walk, and no longer go past the store displays. The Skywalk trend has another, more subtle, knock-on effect. If the well-heeled can take an elevated route to and from their posh buildings, they will have less contact with the millions of poor Bangkokians who can't afford to travel by Skytrain. Less contact presumably means less empathy, and perhaps less inclination to do anything to alleviate mass poverty. In Bangkok, and other cities where the rich want to be cocooned from the masses, it seems that not touching the ground is increasingly the way to go.