The Oak Street Connector (Connecticut Route 34) intersects I-91 at exit 1, just south of the I-95/I-91 interchange, and runs northwest for a few blocks as an expressway spur into downtown before emptying onto surface roads. The Wilbur Cross Parkway (Connecticut Route 15) runs parallel to I-95 west of New Haven, turning northwards as it nears the city and then running northwards parallel to I-91 through the outer rim of New Haven and Hamden, offering an alternative to the I-95/I-91 journey (restricted to non-commercial vehicles). Route 15 in New Haven is the site of the only highway tunnel in the state (officially designated as Heroes Tunnel), running through West Rock, home to West Rock Park and the Three Judges Cave.

What downtown New Haven expressway spur intersects at exit 1 of 1-91?