The Tunnel connects both sides of Astarte while linking up with easy access to the eastern borders of Lapara Town proper.  It is just short of 500 feet long, or 1/10th of a mile, and gives access to the gas station and Route 1 on the mainland using the Astarte Expressway.  Families use the expressway to get to the theme-park 3 sims away.  This was inspired by traditional tunnels in the Northeast, with walkway and exit.