The project series documents "Red Line", a performance that consisted in tracing a red line in the middle of the road with paint sprayer and compressor loaded on the back of a truck. The red line stretched across forty-five kilometres of road and traced the limits of the municipality of Salt Lake City. "The red line rendered visible the boundaries that structure our mental fields of perception and modify our understanding of space."  The performance was carried out in February and March 1972 with a group of students from the University of Utah, in Salt Lake City.
The project series contains photographs of Pettena and his team at work tracing the red line, a drawing, and a map of the Salt Lake City municipality showing the trajectory of the line.
 Marco Scotini, editor. Non-conscious architecture: Gianni Pettena, Sternberg Press, 2018, 235 pages. p. 168.
This project, along with "Clay House" and "Tumbleweeds Catcher" are part of a series of three projects entitled "The Salt Lake Trilogy". The projects were undertaken between April 1971 and March 1972 while Pettena was teaching as a guest professor at the University of Utah, in Salt Lake City. For material related to these projects, see:
- AP207.S1.1972.PR02 Clay House (1972)
- AP207.S1.1972.PR03 Tumbleweeds Catcher (1972)