I think the big picture here is much more important. If tunneling technology is radically improved, we're going to see massive improvements in urban living, including:
• Cleaner air at street level because vehicle exhaust stays underground and can be filtered, which would have massive health and environmental benefits
• Quieter cities with most traffic noise eliminated
• Cooler temperatures since asphalt and vehicle heat are removed from the surface (urban heat island effect)
• More space for trees, parks, and gardens, improving urban greenery.
• Lower stress levels thanks to quieter, greener surroundings.
• Better physical health from more walkable, pedestrian-friendly spaces.
• Cleaner air at street level because vehicle exhaust stays underground and can be filtered, which would have massive health and environmental benefits
• Quieter cities with most traffic noise eliminated
• Cooler temperatures since asphalt and vehicle heat are removed from the surface (urban heat island effect)
• More space for trees, parks, and gardens, improving urban greenery.
• Lower stress levels thanks to quieter, greener surroundings.
• Better physical health from more walkable, pedestrian-friendly spaces.