|Ronald Reagan Memorial Highway/Tollway|
I-88 highlighted in red
|Maintained by IDOT and ISTHA|
|Length||140.60 mi  (226.27 km)|
|Existed||July 1987 –present|
I-80 / IL 5 / IL 92 / IL 110 (CKC) in East Moline
I-290 / I-294 / IL 110 (CKC) in Hillside
|Counties||Rock Island, Whiteside, Lee, Ogle, DeKalb, Kane, DuPage, Cook|
Interstate 88 (I-88) is an Interstate Highway in the US state of Illinois that runs from an interchange with I-80 near Silvis and Moline to an interchange with I-290 and I-294 in Hillside, near Chicago. I-88 is 140.60 miles (226.27 km) long. This route is not contiguous with I-88 in New York. Since 2010, all of I-88 has been part of the Chicago–Kansas City Expressway. The highway also runs through the cities of Aurora, Naperville, DeKalb, and Dixon. East of Rock Falls, the route is a part of the Illinois Tollway system.
The reason for I-88's original designation and continued existence as an Interstate has to do with a technicality in the old National Maximum Speed Law (NMSL). Originally passed in 1973, the NMSL was amended in 1987 to permit 65-mile-per-hour (105 km/h) speed limits on rural stretches of Interstate Highways only. Even though IL 5 was fully up to Interstate Highway standards, it still had to carry a 55-mile-per-hour (89 km/h) limit because of this wording in NMSL. The Illinois Department of Transportation (IDOT) and Illinois State Toll Highway Authority (ISTHA) petitioned the American Association of State Highway and Transportation Officials (AASHTO) to re-designate IL 5 as an Interstate, and in 1987, AASHTO approved the request and assigned the I-88 numbering to the highway.  The NMSL would be completely repealed only eight years later in 1995, but the I-88 shields remain to this day, even though Chicago–Kansas City Expressway (IL 110) markers are being posted throughout the entire length of I-88, since it is now part of the Chicago to Kansas City Expressway project, bannered with special "CKC" logos.
Opened November 21, 1958, it was initially designated as U.S. Route 30 Toll (US 30 Toll), and later IL 190. The original routing extended from the I-294 interchange near Hillside to IL 47 near Sugar Grove. IL 56 was overlapped on the East-West Tollway between North Aurora and Sugar Grove in 1965.
When the East-West Tollway was extended to Dixon in the 1970s, the IL 190 numbering was removed from the stretch between Aurora and Sugar Grove, making that section strictly IL 56. Once complete, the new routing of the combined tollway and freeway between I-80 near the Quad Cities and I-294 became designated as IL 5. In the late 1980s, it was renumbered I-88.
Officially, the tollway portion begins in Rock Falls, starting at the intersection with US 30 at mile marker 44, although the first toll plaza does not appear until after the IL 26 interchange in Dixon, making the section between US 30 and IL 26 technically a freeway. It continues as a tollway until its terminus in Hillside, although there is a free section between exit 76 ( IL 251) and exit 78 ( I-39). West of US 30 to I-80, I-88 is a freeway. The tollway portion is 96 miles (154 km) long.
After the death of Illinois native and former President Ronald Reagan in 2004, the Illinois State Toll Highway Authority (ISHTA) voted to rename the toll roadway "Ronald Reagan Memorial Tollway" in his memory, as it passes near his birthplace of Tampico and grazes the south outskirts of his boyhood hometown of Dixon. The tollway portion of I-88 was previously known as the "East–West Tollway" and is still displayed as such on some signs near Chicago.
Although a federal law, 23 U.S.C. § 111, prohibits the operation of commercial rest areas constructed after January 1, 1960, on Interstate Highways, the DeKalb oasis was constructed at milepost 93 in 1975, prior to the route's designation as I-88 and remains in operation.
From 2005 lasting through 2012, ISTHA reconstructed and widened much of the original portion of I-88, between York Road and IL 56. Approximately $991.6 million was budgeted for I-88 over that period.  Between 2005 and 2009, I-88 was reconstructed and widened to four lanes in each direction between IL 59 and York Road, with work progressing gradually from west to east. The project included a reconstruction and reconfiguration of the Naperville Road interchange.  Between IL 56 and the Aurora Toll Plaza, I-88 was reconstructed and widened to three lanes, including the reconstruction of the IL 31 interchange and new bridges over the Fox River.  
A $36 million interchange at Eola Road in Aurora opened on November 20, 2009, after approximately 10 years of planning and less than one year of actual construction.  Toll booths at this ramp accept only I-PASS, and have no provisions for accepting cash payments.  
This section contains a table that is missing mileposts for one or more junctions.
|Rock Island||East Moline||0.00||0.00||IL 5 / IL 92 west – Moline, Rock Island||Continuation beyond western terminus; west end of IL 92 overlap|
I-80 / IL 110 (CKC) south to I-74 – Des Moines, Peoria
|Signed as exits 1A (east) and 1B (west); west end of IL 110 overlap; I-80 exits 4A–B|
|2||Old IL 2|
|Joslin||6||IL 92 east – Joslin||East end of IL 92 overlap|
|Hillsdale||10||Hillsdale, Port Byron|
|Whiteside||Erie||18||Erie, Albany||To IL 84|
|Lyndon||26||IL 78 – Morrison, Prophetstown||Former IL 2|
|Rock Falls||36||US 30 west – Clinton, Rock Falls, Sterling|
|41||IL 40 – Rock Falls, Sterling|
|44||US 30 – Joliet, Rock Falls|
|Lee||||Eastern end of Ronald Reagan Memorial Highway|
Western end of Ronald Reagan Memorial Tollway
|Dixon||54||IL 26 – Dixon|
|Dixon Toll Plaza|
|Ogle||Rochelle||76||IL 251 – Rochelle, Mendota|
|78||I-39 / US 51 – Rockford, Bloomington, Normal||I-39 exits 97A-B; signed as exits 78A (south) and 78B (north).|
|DeKalb||DeKalb||86.25||138.81||DeKalb Toll Plaza|
|91||146||91||To IL 38 / IL 23 / Lincoln Highway / Annie Glidden Road – DeKalb, Cortland, Creston, Malta||Toll on eastbound exit and westbound entrance ramps|
|94.25||151.68||94||To IL 38 / Lincoln Highway / Peace Road – DeKalb, Cortland, Creston, Malta||Toll on westbound exit and eastbound entrance ramps|
|Kane||Sugar Grove||109||175||109||IL 47||Eastbound exit and westbound entrance|
|Aurora||113.75||183.06||113||IL 56 west to US 30 / IL 47 – Sugar Grove||West end of IL 56 overlap; westbound exit and eastbound entrance|
|114.5||184.3||114||Orchard Road||Toll on eastbound exit and westbound entrance ramps, was exit 115|
|North Aurora||116.75||187.89||117||IL 31 / IL 56 east||East end of IL 56 overlap; toll on eastbound exit and westbound entrance ramps|
|Aurora||118||190||Aurora Toll Plaza|
|119.25||191.91||119||Farnsworth Avenue||Toll on westbound exit and eastbound entrance ramps; signed as exits 119A and 119B westbound|
|DuPage||121.25||195.13||121||To Eola Road||I-PASS only on westbound exit and eastbound entrance ramps|
|Naperville||123.5||198.8||123||IL 59||Diverging diamond interchange as of 2016|
|Warrenville||125.5||202.0||125||Winfield Road||Toll on eastbound exit and westbound entrance ramps|
|Naperville||127||204||127||To Naperville Road||Toll on eastbound exit and westbound entrance ramps|
|Lisle||130||210||130||IL 53 (Lincoln Avenue)||Westbound exit and eastbound entrance|
I-355 (Veterans Memorial Tollway) – Joliet, Northwest Suburbs
|I-355 exit 20; signed as exits 131A (south) and 131B (north) westbound; signed as exits 131 (south) and 132 (north) eastbound|
|134.5||216.5||134||Highland Avenue||Toll on eastbound exit and westbound entrance ramps|
|Oak Brook||135||217||Meyers Road Toll Plaza (eastbound)|
|136.5||219.7||136||Midwest Road||Eastbound exit and entrance only; toll on eastbound entrance ramp|
|137.3||221.0||137||IL 83 south (Kingery Highway)||No westbound entrance; toll on eastbound entrance ramp|
|138||To IL 83 north (Kingery Highway) / 22nd Street (Cermak Road)||Westbound entrance and exit only; toll on westbound entrance ramp|
|York Road Toll Plaza (westbound)|
I-294 south ( Tri-State Tollway) / York Road – Indiana
|Eastbound exit and westbound entrance; exit includes direct exit ramp onto York Road|
I-294 north ( Tri-State Tollway) / I-290 west (Dwight D. Eisenhower Expressway) – Milwaukee, Rockford
|Eastbound exit and westbound entrance|
I-294 south ( Tri-State Tollway) / IL 38 west ( Roosevelt Road) – Indiana
|Westbound exit and eastbound entrance|
|—||I-290 east (All trucks) to US 12 / US 20 / US 45 ( Mannheim Road) – Chicago||Eastbound exit only|
I-290 / IL 110 (CKC) east (Dwight D. Eisenhower Expressway) – Chicago
|Eastern terminus; east end of Ronald Reagan Memorial Tollway; exit 15A on I-290|
|1.000 mi = 1.609 km; 1.000 km = 0.621 mi|
- Mehler, Neil H. (July 6, 1987). "Road with Many Names Gets a New One". Chicago Tribune (National ed.). p. C3. Retrieved February 16, 2008.
- Illinois Technology Transfer Center (2006). "T2 GIS Data". Illinois Department of Transportation. Retrieved November 8, 2007.
- Staff (September 2007). "Executive Summary". Congestion-Relief Program Summary (PDF) (Report). Illinois State Toll Highway Authority. pp. 3–6. Archived from the original (PDF) on September 27, 2011. Retrieved February 28, 2011.
- Staff (May 5, 2009). "Washington Street to Finley Road Rebuild & Widen Project & Naperville Road Interchange" (PDF). Reagan Memorial Tollway. Illinois State Toll Highway Authority. Retrieved September 20, 2014.
- Staff (December 2, 2009). "Aurora Toll Plaza to Orchard Road Rebuild & Widen Project" (PDF). Reagan Memorial Tollway. Illinois State Toll Highway Authority. Retrieved September 20, 2014.
- "I-88 Rebuild and Widen Project" (PDF). Reagan Memorial Tollway. Illinois State Toll Highway Authority. Retrieved September 20, 2014.
- Sanchez, Robert (November 20, 2009). "Long-Awaited Eola Road/I-88 Interchange Opens". Daily Herald. Arlington Heights, IL. Retrieved January 3, 2010.
- Griffin, Jake (April 15, 2009). "Tollway Expects Eola Interchange at I-88 by End of Year". Daily Herald. Arlington Heights, IL. Retrieved January 2, 2010.
- Smith, Gerry (November 27, 2009). "New I-88 Interchange at Eola Road Opens in Aurora". Chicago Tribune. Retrieved January 2, 2010.
|Wikimedia Commons has media related to Interstate 88 (Illinois).|