What does this number measure?
The Boring Company's FAQ, updated on 14 August 2026, states an internal diameter of 12 feet for each Music City Loop tunnel in Nashville, United States. Using the international foot of 0.3048 m, this gives 12 × 0.3048 = 3.6576 m, or approximately 3.66 m. The compared diameter runs from one inner surface to the other. The wall, ground and illustrated fittings are not part of this measurement. The project was listed as under construction when consulted on 2 November 2026: this reference represents the planned specification, not a survey of the completed tunnel. The boring machine's cutting-head diameter, depth below ground and network length are different quantities.
Compare the stated dimensions
The comparison uses the number in each fact sheet: altitude, height, diameter, length or distance, depending on the reference. Two values in metres do not necessarily describe the same property.
Source and limitations
Announced design diameter for a project under construction, not an acceptance measurement. The conversion is exact; the precision of the 12-foot specification is not provided. Wall thickness and surroundings are illustrative.
Interpreted cross-section of the planned Music City Loop tunnel. Only the inner diameter of the foreground ring is calibrated; wall thickness, roadway and depth are illustrative.