IN the alley connecting Palmerah Market in South Jakarta with the nearby train station, a speed bump had been installed. It was still new, judging by the fresh yellow and black stripes painted on it.

Its purpose is unclear. Perhaps to prevent motorcycles from speeding. In fact, this alley is only 1.5 meters wide. It is flanked on both sides by food stalls and street vendors. During rush hour—the peak number of commuters getting on or off t