Source: International Union of Railways
High speed rail has been a technology actively contributing to regional space / time convergence. The setting of high speed rail systems considerably improved travel times between the metropolitan areas it services, on with average a 50% reduction. In many cases (such as Paris / Lyon on the Paris / Marseille axis) the drop in travel time has placed new areas within commuting range, implying that some HSR corridors can become commuter rail lines. The high speed train system has also the advantage of servicing central areas (for most stations) with an overall higher level of accessibility to the city. By including travel time to stations commonly well serviced by public transit, the high speed train system can compete effectively with short and medium distance air transport. In recent years, several new systems were brought online in Asia, including in South Korea (2004), Taiwan (2007) and China (2009). In the case of China the service time improvements were particularly impressive since the existing rail passenger network was slow and congested. HSR services that are able to service major cities location 250 to 500 km apart in less than three hours are able to compete effectively with air travel to become the dominant intercity mode.