Miami-Dade County’s plan to build six new transit corridors advanced in 2020, and five of the six corridors now have a mode of transportation selected.

The mass transit expansion is known as the SMART Plan.

Here’s a look at what commissioners chose to build for each of the corridors:

• Beach Corridor – A monorail will run 3.45 miles, from downtown Miami’s Omni station to 5th Street in South Beach.

• Northeast Corridor – Commuter rail has been selected, ...