Interstate 370 Missouri
Missouri 370 is a 12 mile long freeway connecting I-270 with I-70 in the vicinity of St. Charles, northwest of St. Louis. Interstate 370 currently does not exist in Missouri. Although Missouri 370 is a freeway, it was constructed without Interstate funding. No official plans are in place to redesignate the state highway as an Interstate.1
Missouri 370 was considered as I-370, but it would only be approved by the American Association of State Highway and Transportation Officials (AASHTO) if it were designated as I-870.2,3 Missouri objected to this, because Interstate 870 was a designation that was supposedly being reserved for a bypass route in Columbia.4
Missouri 370 was originally planned as Missouri 115, but it was renumbered to be consistent with the numbering of I-70 and I-270. Here is a brief chronology of the freeway:5
- August 3, 1984 – Missouri 115 preliminary alignment adopted by the Missouri Highways and Transportation Commission for section from Interstate 270 to Missouri 94
- 1985 – Highway 115 Northern Corridor Commission formed to promote the development of the new freeway
- April 1987 – gasoline tax approved by voters; funds used for Missouri 370 extension from Missouri 94 to Interstate 70
- December 1988 – Construction began with new interchange at Interstate 270
- December 16, 1992 – Discovery Bridge and first leg of Missouri 370 opens ahead of schedule at a ribbon-cutting ceremony
- 1997 – remaining section from St. Charles to St. Peters opens; old Missouri 115 bridge demolished
East End – Bridgeton, MO
West End – St. Peters, MO
Mileage – 12.96
Cities – St. Peters, St. Charles, Bridgeton, Hazelwood
- Junctions –
Source: MoDOT FlexMap Viewer
Highway 370 Annual Average Daily Traffic (AADT)
|Location||Vehicles per day|
|Exits 1B to 2||46,337|
|Exits 2 to 5||51,979|
|Exits 5 to 7||51,421|
|Exits 7 to 9||58,267|
|Exits 9 to 11||52,288|
East End – Bridgeton, Missouri
West End – St. Peters, Missouri
- “They built it, and they came: Highway 370, Discovery Bridge have served many purposes.” Suburban Journals of Greater St. Louis (MO), December 12, 2006.
- Interstate 370 – Kurumi.com (Scott Oglesby)
- Boor, Anthony “Re: MO S.R. 370 and The Boeing Company (was Re: I-180 now more useless than ever!).” Online posting. December 18, 2001. news misc.transport.road.
- Dowd, Brian “Re: I-64 st louis experience” Online posting. November 10, 2004. news misc.transport.road.
- Dowd, Brian. Personal email, May 25, 2004.
- Dowd, Brian. “Mo Highway notes” Personal email, November 22, 2004.
Page updated February 1, 2019.