turn lanes on the entire length of Illinois 120. The remaining section of highway, although only briefly limited-access, does have limited signalized intersections which keeps traffic flowing at a more constant rate. It first passes under a grade separation at Illinois Route 21 (Milwaukee Avenue) and goes over the Des Plaines River before forming an interchange with Interstate 94 (Tri-State Tollway). Only southbound access is permitted to I-94; northbound access is available via IL 21. It next enters part of the Waukegan area and shortly encounters an at-grade intersection with O'Plaine Road and then continues with more grade separation at the Canadian Pacific Railway (CP) tracks and Greenleaf Avenue. Interchanges with IL 43 (Waukegan Road) and U.S. Route 41 (Skokie Highway) closely follow one another with a brief transition into Park City located between these two junctions. It can be confusing in this area as there is no direct access to northbound US-41 or southbound IL-43, which terminates immediately north at US-41. Illinois 120 loses its divided highway status after traveling over the Union Pacific (UP) tracks and passing by its last stretch of businesses as it reenters Waukegan. It soon reaches the commercially developed, signalized intersection of Illinois Route 131 (Green Bay Road) where it terminates as a state route; Belvidere Road continues east as a local road. History State Bond Issue (SBI) Route 120 originally ran from Havana to Mason City in west-central Illinois. In 1939 this became IL 119, and in 1951, U.S. Route 136. In the meantime, in 1941 Illinois 120 replaced Illinois Route 20 to avoid confusion with nearby U.S. Route 20. In 1972, the designation was removed east of IL 131. During the early 1990s, plans came about to widen 5.7 miles of roadway in McHenry and Lake counties. The project extended from River Road in McHenry to east of Illinois 60. These plans also included the construction of a short southern bypass around the town of Volo. By 1994, the work had concluded which resulted in four concrete travel lanes, providing easier access between the two counties. In 2000, a $4.6 million construction project was completed at the intersection of US-45. The improvements that took place to Illinois 120 were: expanding to two lanes in each direction and adding a right turn lane to the eastbound approach. The most recent major construction that has taken place was between August 2007 and July 2008