Interstate 370 Missouri
Overview
Missouri Route 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 Route 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
Route 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
Mileage by State
| Missouri | 12.96 mi |
Data Sources
MoDOT HPMAP. https://traveler.modot.org/hpmaps/
History
Missouri Route 370 was originally planned as Missouri Route 115, but it was renumbered to be consistent with the numbering of I-70 and I-270. A brief chronology of the freeway:5
- August 3, 1984 - Route 115 preliminary alignment adopted by the Missouri Highways and Transportation Commission for section from Interstate 270 to Route 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 Route 370 extension from Route 94 to Interstate 70
- December 1988 - Construction began with new interchange at Interstate 270
- December 16, 1992 - Discovery Bridge and first leg of Route 370 opens ahead of schedule at a ribbon-cutting ceremony
- 1997 - remaining section from St. Charles to St. Peters opens; old Route 115 bridge demolished
East End 
‐ Bridgeton, MO
West at 
Missouri Route 370 is a viable alternative from I-270 for Interstate 70 west to Wentzville and Kansas City via the Discovery Bridge between Bridgeton and St. Charles. 10/16/04
West End 
‐ St. Peters, MO
West at
Crossing into the city of St. Peters, I-70 advances one mile west to Exit 224 with Route 370 east.
References
- "They built it, and they came: Highway 370, Discovery Bridge have served many purposes." Suburban Journals of Greater St. Louis (MO), December 12, 2006.
- Oglesby, S. Interstate 370. Kurumi.com. Retrieved from http://www.kurumi.com/roads/3di/i370.html
- Boor, Anthony. (2001, December 18). Re: MO S.R. 370 and The Boeing Company (was Re: I-180 now more useless than ever!). [Online posting]. news misc.transport.road. Retrieved from https://groups.google.com/forum/?hl=en#!msg/misc.transport.road/41ap9EfI028/se7sLjcnrVoJ
- 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.