For several months now, the noise of heavy machinery has tormented students living in the northern section of the Yard. Last spring many students in that area complained that they were unable to study or to sleep because of the constant banging and pounding.

The men and machines responsible for this noise come from the Dematteo Construction Company, which was hired by Harvard to build a huge underground passageway for cars just north of the Yard so that students could walk to Memorial Hall and the Law School without encountering the traffic.

When construction is completed next June, there will be no cars at all on the road between the northwest corner of the Yard and the fire station at Broadway and Cambridge St. The former roadway will be landscaped with grass, trees and shrubs; new sidewalks will connect the Yard with Lowell Lecture Hall, the Law School, and other University buildings in the "north campus." The project's total cost to Harvard will be about $3 million--$2.8 million for construction and the rest for administrative expenses and landscaping.

Work on the underpass is now about 25 per cent complete--and slightly behind schedule. One factor slowing down construction is this summer's unusually heavy rainfall. The underpass is still nothing more than a gigantic hole in the ground and the rainwater it collects has made construction in some spots very difficult, if not impossible.

Although the City of Cambridge was not a party in the contract between Harvard and the construction company, it did have to give its approval to the plans. The construction of the underpass has caused extensive disruption in traffic all over the City; the new traffic pattern--which has turned seven formerly two-way thoroughfares in the Harvard Square area into one-way streets--was required to ease the problem.

When work is completed next summer, cars moving west along Broadway or Cambridge St. will go sharply downhill beginning at the fire station. The underpass itself will begin at a spot near Hunt Hall and will extend approximately 400 feet to about Phillips Brooks House where the cars will climb back to the surface. Traffic heading in the opposite direction will begin the descent close to Mower Hall. Before climbing back to the surface, these cars will be able to choose between heading left on Cambridge St. or right on Broadway.

At first traffic will be limited to two lanes in each direction, but the underpass will be equipped for future expansion to three lanes heading both east and west.

According to Cambridge's traffic director, Robert E. Rudolph, the four-major bottlenecks in the Harvard Square area have traditionally been Harvard Square, Brattle Square, the intersection of Cambridge St. and Massachusetts Avenue, and the intersection of Kirkland and Cambridge Streets. Rudolph's new traffic pattern is designed to cut down the first three problems; the new underpass is expected to handle the fourth. When the underpass is completed, the intersection of Kirkland and Cambridge Streets will be eliminated and cars are expected to move much more quickly through the area. But until work stops next June, students living close to the underpass will probably not think about its advantages--either to cars or to pedestrians--but only about the incessant banging of machinery.