built between 1929 and 1951, the highway had narrow confines—which could not accommodate trucks—and sharp s exit ramps that made it obsolete almost immediately. maintenance was minimal, and the use of corrosive salts to de-ice the highway in winter accelerated its decay. when chunks of its facade began to fall off due to lack of maintenance, and a truck and car fell through it at 14th street in 1973, the highway was shut down, and a debate began whether to renovate it or dismantle it. attitudes to urban planning had changed in the intervening decades, and the decision was made not to repair the decaying structure.