The chief engineer was Vernon R. Covell of the Allegheny County Public Works Department.

[citation needed] The tunnel itself is characterized by twin bores of horseshoe cross-section, and bends halfway through.

[citation needed] A legend mentioned by the site involves a notion that the bend in the tunnel was a mistake, and whoever was responsible committed suicide in shame.

Author Bruce S. Cridlebaugh suspects the bend was related to mines or other geological factors, property rights (including Duquesne University), or alignments with existing or proposed roads.

[3] The tunnels were named in honor of Joseph G. Armstrong, County Director of Public Works.