Suburban Transit System was renamed in 1938 from South West Towns Bus Line, reflecting an unsuccessful attempt to expand into other suburbs.
In the mid 1970's, RTA assigned universal numbers to all suburban bus routes, usually adding 380 to the Suburban Transit System route numbers.
380 - Clearing - rush hour service introduced 3/12/84 between Ford City Mall via 73rd St. to Oak Park Ave. Replaced 11/1/93 by rush hour extension of #382 route, serving newly opened Midway Airport CTA rapid transit station.
381 - 95th St. - was Suburban Transit System route #1. Introduced in 1921 by South West Towns Bus Line on 95th St. between Vincennes. Ave and Kean Ave. Route included a branch south via Ridgeland Ave., 111th St., Harlem Ave., 119th St., 80th Ave., 123rd St., 96th Ave., 143rd St., 98th Ave. to 144rd St. in Orland Park. In 1927, service extended to Halsted/63rd St. CTA station via Morgan Blvd. In 1941 Ridgeland branch was cut back to operate via Ridgeland Ave., 111th St., Harlem Ave., 127th St. to 86th Ave./123rd St. In 1982, CTA terminal was changed from Halsted/63rd St. to 95th St./Dan Ryan, even though CTA line to 95th/Dan Ryan had opened in 1969. A shuttle route #4 had been introduced in 1969 on 95th St. between Vincennes and the Dan Ryan terminal. Ridgeland branch became part of new route #384 effective 6/5/78. Effective 4/19/82 amidst RTA funding crisis, service suspended east of Ashland/95th St. Effective 3/12/84, route restored to 95th/Dan Ryan CTA station, and extended south via 88th Ave. to Moraine Valley College. Effective 11/24/2008, service revised to serve Bridgeview Court House at 103rd St./76th Ave., discontinuing service on 95th St. west of 76th Ave. On that date, route #385 revised to provide some service on 95th St. between Roberts Rd. (80th Ave.) and 88th Ave. Effective 6/7/2009, some route #381 service restored via 95th St. and 88th Ave.
382 - Central/Clearing - was Suburban Transit System route #3, operating as far north as Ford City Mall. Operated via Narragansett Ave. north of 87th St., and via 79th St. east to Cicero Ave. Effective 6/5/78 when new #384 was created, began operating via Central Ave. as far north as 79th St. Present routing adopted 11/1/93 upon opening of CTA rapid transit line at Midway Airport, and during rush hours serving Clearing industrial district, replacing route 380. Effective 6/7/2009 as part of a major restructuring of south suburban Pace routes, mid day service discontinued. Service suspended effective 4/20/2020 due to covid-19 pandemic.
383 - Cicero Ave. - was Suburban Transit System route #2. Introduced in 1929 by South West Towns Bus Line from 63rd St. to 103rd St., extended by late 1960's to 111th St. with limited service to 159th St. Effective 9/17/79, extended south of 159th St./Cicero Ave. to Hazel Crest train station. Extension discontinued 8/31/82, and discontinued north of Ford City Mall. Extended north to Midway Airport 10/31/93 upon opening of CTA rapid transit line there.
384 - Narragansett-Ridgeland - introduced 6/5/78 between Ford City Mall and 86th Ave./123rd St., replacing a branch of route #381 and a portion of route #382. Around 1979 extended south to Orland Square Mall via various streets, also serving Palos Community Hospital. Extended north to Midway Airport 10/31/93 upon opening of CTA rapid transit line there. Effective 6/7/2009 as part of a major restructuring of south suburban Pace routes, route discontinued south of 111th St.
385 - 87th/111th/127th - in 1929, a route was introduced by South West Towns Bus Line on 111th St. between Western Ave. and Ridgeland Ave., but that route did not survive long. The route was tried again in 1949, but was discontinued again, except for school tripper service. From 1938 to 1939, an experimental route existed on 127th St. between Western Ave. and Harlem Ave. Segment on Roberts Rd. was introduced during World War II between Archer Rd. and 106th St., discontinued in early 1950's north of 95th St. and made a branch of route #381 south of 95th St. Branch made a part of route #385 upon introduction 11/10/75. Later extended south to 127th St./Homan Ave. Extended south to Rivercrest Shopping Center 8/17/92, and extended north to Midway Airport 11/1/93 upon opening of CTA rapid transit line there.
386 - Harlem - introduced 3/7/77 between Archer Ave./Harlem Ave. and 127th St./Route 83. Rush hour extension to Blue Island train stations introduced 6/5/78, extension suspended 10/4/92 amidst RTA funding crisis. Rush hour extension restored 3/12/84, with base service extended south to Orland Square Mall via Harlem Ave., 131st St., and La Grange Rd. Rush hour extension cut back to 127th St./Homan Ave., when route #385 was extended through Blue Island. Effective 11/1/93, extended to Midway Airport via 63rd St. upon opening of CTA rapid transit line there. Effective 6/7/2009 as part of a major restructuring of south suburban Pace routes, service to Orland Square Mall replaced with revision of route #379. South segment revised instead to serve Tinley Park, replacing portion of route #354 primarily via Oak Park Ave. and 183rd St. On that date, rush hour extension via 127th St. discontinued.
387 - SeatGeek Stadium - introduced 3/12/2017 between Midway Airport and SeatGeek Stadium, originally named Toyota Park, for special events. Previously, special event service had been provided by extra trips of route #386. Service suspended in 2020 due to covid-19 pandemic.
From 6/6/81 to 8/3/81, Suburban Transit System was shut down because of the RTA funding crisis at the time, when the RTA did not have the cash to pay to keep the company operating. After service was restored, Sunday service was finally restored 9/20/87.
391 - Near West Suburbs-UPS - introduced 1/25/99, discontinued around 2012. Operated by Pace West Division.
392 - Little Village-UPS - introduced 3/20/2000. Operated by Pace West Division.
393 - Melrose Park-Addison UPS - introduced 7/31/2000, discontinued 8/31/2009. Connected the CTA Green Line and near west suburbs with the UPS facility in the suburb of Addison. Operated by Pace West Division.
394 - NW Chicago-Addison UPS - introduced 11/24/2003, discontinued 8/31/2009. Connected various points on Chicago's northwest side with the UPS facility in the suburb of Addison. Operated by Pace West Division.
395 - CTA 95th St. Station-UPS - introduced 7/13/98. Operated by Pace Southwest and South Divisions.
396 - Rosemont CTA Station-UPS - short lived route introduced 6/17/2002. Operated by Pace Northwest Division.
397 - Blue Island-Moraine Valley College-UPS - introduced 6/28/99, discontinued around 2012. Operated by Pace South Division.
398 - Olive Harvey College-UPS - introduced 11/6/2000, discontinued 11/2001. Operated by Pace Southwest and South Divisions.