Route Numbers To Be Changed SPRINGFIELD -- Six state highway route numbers In the Elgin and Chicago districts of the Division of Highways will be changed, Francis S. Lorenz, public works director, announced today. The changes will be made during February by sign erection crews. The Division of Highways continually strives to simplify the route numbering system by eliminating confusing and unnecessary markings. This is generally accomplished by extending other routes. Alternate route numbering and the use of a letter in conjunction with a numeral is considered unsatisfactory. Changes to be made Include: Lake County, Illinois 59A changed to 111. 60; Cook and Will Counties, Illinois 4 A removed from Archer Ave. and Illinois 171 extended from 55th St. in Summit to Joliet; Will and Grundy Counties, Alt. US 66 eliminated, 111. 53 extended south to Gardner; Will County, 111. 7 extended from Lockport to Joliet over 111. 53, Theodore St. andLarkln Ave.; Boone and Winnebago Counties, 111. 5 eliminated by extending US 20 over present 111. 5 from Belvidere to Rock-ford Bypass (US 20); Boone and Winnebago Counties, US 20 from Belvidere to Mulford Road will be marked as Business Route US 20, which will then be continuous from Belvidere through Rockford to US 20 west of Rock-ford, temporary US 20 will be removed from Mulford Road.