Motorways and Shinkansen bullet train lines constructed at the time helped form the foundations of Japan 's economic growth .
Motorways and Shinkansen bullet train lines constructed at the time remain indispensable to the country 's economic and cultural infrastructure .
Motorways and Shinkansen bullet train lines constructed at the time helped form the foundations of Japan 's economic growth , and remain indispensable to the country 's economic and cultural infrastructure .