Credit: KGO-TV

The $405 million fourth bore of the Caldecott Tunnel in California is nearing completion and on track to open to traffic later this year, with the final cost coming in approximately $15 million less than the original cost estimates, according to this article. The new bore will feature 19 massive jet fans, linear heat detectors and nitrous-oxide and carbon-monoxide sensors, all to work together in case of fire or emergency.

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