第18期 · 公共交通比修路更值得投资吗

The battle between asphalt and rail is, at its core, a debate about the kind of cities we wish to inhabit. For decades, road-building has been the default response to congestion, yet the evidence increasingly suggests that this approach is not merely ineffective but self-defeating. I firmly agree that public transport deserves a far larger share of infrastructure budgets, though I would stop short of advocating the complete abandonment of road investment, recognising that roads remain indispensable for last-mile connectivity and freight logistics. The case against road-centric investment rests on a phenomenon known as induced demand — one of the most robust yet counterintuitive findings in transport economics. When road capacity is expanded, the initial reduction in travel time is quickly eroded as drivers who previously avoided peak hours, used alternative routes, or opted for public transport now switch back to driving. Within a few years, congestion returns to its original level — or worse. Los Angeles spent billions widening its freeways over three decades, only to see average commute times lengthen. Seoul's dismantling of an elevated highway and its replacement with a restored stream and pedestrian corridor, by contrast, did not produce the traffic Armageddon that critics predicted; drivers simply adjusted their behaviour. The lesson is clear: you cannot build your way out of congestion. Public transport, by contrast, operates on a fundamentally different logic. A single metro line can move upwards of forty thousand passengers per hour in each direction — a volume that would require a twenty-lane motorway to match. Moreover, rail-based systems produce negligible emissions per passenger-kilometre compared with private vehicles, making them indispensable tools in the pursuit of decarbonisation. The benefits spill well beyond the transport sector: compact, transit-oriented urban development reduces sprawl, preserves agricultural land on city peripheries, and fosters the street-level economic activity that makes cities vibrant. Tokyo's rail network, which carries over forty million passengers daily with legendary punctuality, demonstrates that when public transport is sufficiently dense and reliable, car ownership becomes a lifestyle choice rather than a necessity — with profound implications for air quality, public health, and land use. That said, a wholesale abandonment of road investment would be both impractical and inequitable. Rural communities, where population densities render mass transit economically unviable, depend on roads for access to healthcare, education, and markets. The freight industry, which underpins everything from supermarket shelves to e-commerce deliveries, cannot be shifted onto rails overnight — and in many geographies, the rail network simply does not reach the points of final distribution. The challenge, therefore, is not to stop building roads but to rebalance priorities. Road spending should pivot from capacity expansion — which the evidence shows is futile — toward maintenance, safety improvements, and dedicated bus lanes that give public transport a speed advantage over private cars. Congestion pricing, as implemented in London and Singapore, can further tilt the playing field by making drivers internalise the social costs of their journeys, while generating revenue that can be ring-fenced for public transport investment.