Interstate 370 Maryland

Routing

Interstate 370 connects I-270 with the Intercounty Connector (ICC) toll road east in Montgomery County, Maryland. Located between the cities of Gaithersburg and Rockville, I-370 carries commuter traffic west to Sam Eig Highway and east to Shady Grove Metro Station. Prior to construction of the ICC, I-370 concluded at the exchange with Shady Grove Road and the access road to Shady Grove Station. Inventoried as Maryland 200A, this connection remains but is no longer included in the Interstate System.

Designated Maryland State Route 200, the Intercounty Connector extends east from a trumpet interchange with Interstate 370 and Maryland 200A. The 18.8-mile long toll road winds through suburban areas north of the Capital Beltway to Interstate 95 and U.S. 1 near Laurel. Operated by the Maryland Transportation Authority (MDTA), the expressway uses all electronic toll (AET) collection.

History

AASHTO approved Interstate 370 between I-270 and the vicinity of Shady Grove on November 15, 1975. The freeway opened to traffic on December 17, 1988.1 Completion of the Intercounty Connector Project shortened I-370 from 3.13 to 2.54 miles. The truncation to Maryland 200 was conditionally approved by AASHTO on November 16, 2012.

Intercounty Connector

A Draft Environmental Impact Statement (DEIS) was released for the Intercounty Connector project in December 2004, with a toll feasibility analysis completed afterwards.2 The preferred corridor was the southern alignment.3 A Record of Decision was released by the Federal Highway Administration (FHWA) on May 30, 2006.4

Construction on the ICC began in November 2007 after nearly 50 years of debate on whether to build it.5 The ICC is not planned to be designated as a part of Interstate 370.6 Plans called for the six-lane, $2.4 billion tollway to fully open in 2012. The phases for construction were:7

  1. Contract A - connect Interstate 370 and MD 97 / Georgia Avenue (7.2 miles, construction from 11/13/07 to Fall 2010; $478.7 million cost)
  2. Contract B - connect MD 97 / Georgia Avenue with U.S. 29 (7.0 miles, construction from Mid-2008 to Late 2011; up to $460 million cost)
  3. Contract C - connect U.S. 29 with I-95 (3.7 miles, construction from 1/14/08 to Late 2011, $513.9 million)
  4. Contract D - construct collector distributor roadway system between ICC and I-95 (three miles at a cost up to $75 million) - construction slated from 2010 to 2011 or 2012

The ICC fully opened between I-370 and I-95 on November 22, 2011. The 1.5 mile extension from I-95 east to U.S. 1 at Laurel opened to traffic on November 10, 2014.

Highway Guides

Western Terminus - Interstate 270 / Sam Eig Highway - Gaithersburg, Maryland
Perspective from Interstate 370 west
A left exit joins Interstate 370 west with I-270 south to Washington. I-370 formally ends 0.6 miles ahead by Washingtonian Boulevard. The freeway freeway extends 0.2 miles further to a signalized intersection with Fields Road. Photo taken 06/20/12.
Perspective from Interstate 370 east
The zero milepost for Interstate 370 per the MDOT Highway Location Reference (HLR) is located at the merge point from the I-270 north to Sam Eig Highway westbound ramp. This point falls within the diamond interchange at Washingtonian Boulevard. Photo taken by Jeff Royston (06/10/06).
An auxiliary lane opens eastbound from Washingtonian Boulevard to I-270 south. Shady Grove Metro Station was greened out for Interstate 370. Photo taken 06/20/12.
The connection from I-370 east to I-270 north to Frederick is the lone loop ramp within the turbine interchange between the two freeways. Photo taken 06/20/12.
The lone eastbound confirming marker was posted at the Oakmont Avenue underpass. The assembly was removed during expansion of I-370 to six lanes in 2008-09. Photo taken by Jeff Royston (06/10/06).
Perspective from Interstate 270 north
Exit 9A departs from the Local Lanes of Intersttae 270 north for both I-370 east to the Inner County Connector (MD 200) and Sam Eig Highway west to MD 119 (Great Seneca Highway). Photo taken by 08/04/13.
Eastern Terminus - Maryland 200 / Inner County Connector - Washington Grove, Maryland
Perspective from Interstate 370 east
A trumpet interchange (Exit 3B) joins the east end of Interstate 370 with unsigned MD 200A south to Shady Grove Road and Shady Grove Metro Station and the ICC east to Prince George's County. Photo taken 06/20/12.
An end shield for I-370 previously stood within the six-ramp parclo interchange connecting MD 200A with Shady Grove Road. Photo taken by Jeff Royston (06/10/06).
Perspective from Maryland 200 (ICC) west
Westbound Maryland 200 (ICC) transitions into Interstate 370 beyond the departure of Exit 3 for Maryland 200A south to Shady Grove Road. The lone indication of I-370 along the ICC west is this assembly. Photo taken 06/20/12.
Perspective from Maryland 200A north
Interstate 370 extends west from MD 200 (ICC) and the exchange with MD 200A. I-370 formerly curved westward here ahead of MD 355 in Gaithersburg. Photo taken 06/20/12.

Sources:

  1. Interstate 370 @ Wikipedia.org.
  2. "Maryland's ICC may not need any tax money - for Maryland Taxpayers Association.quot; Toll Road News, March 24, 2005.
  3. "Southern Route for Connector Endorsed" Washington Post, February 4, 2005.
  4. Posts from misc.transport.road newsgroup: "Maryland ICC Record of Decision and Groundbreaking" by Scott M. Kozel, 05/31/06 and "Re: Maryland ICC Record of Decision and Groundbreaking" by Scott M. Kozel, 05/31/06.
  5. "With Obstacles Overcome, Highway Work Begins: Quietly, Barriers and Dirt Emerge at Scattered Sites." Washington Post, November 29, 2007.
  6. Wolf, Joe. "Another Interstate Guide update.quot; Personal Email, 12/17/07.
  7. ICC Project Schedule http://www.iccproject.com/project-schedule.php, accessed on January 2008.

Page updated February 20, 2019.