Why are Tokyo’s commuter trains often crowded during rush hours?

The Tokyo-Yokohama metropolitan area is home to one-fourth of Japan's total population, creating an immense concentration of people within a single region. This high population density, combined with the significant demand for daily transit, results in extreme congestion on commuter rail lines during rush hours.123

While these rail systems are highly regarded for their safety, punctuality, and cleanliness, they frequently operate beyond their designed passenger capacity. Although service providers have gradually expanded operations to address this high demand, the sheer volume of commuters remains a persistent challenge. Furthermore, while road networks exist, they are often inadequate for the volume of vehicular traffic, reinforcing the reliance on the rail network as the primary mode of transport for the region's massive workforce.2345