Interstate 225

Length: 12 miles (I-25 in Denver to I-70 in Aurora)
Exits: 10
Counties: 3 (Adams, Arapahoe and Denver )
Cities: 2 ( Aurora and Denver )
Start of Construction: 1964
End of Construction: May 21, 1976
Initial Construction Costs: $27.5 million

National Impact

I-225 connects with I-25 and I-70, allowing motorists to link with states east, west, north and south of Colorado.

I-225 was built in stages coming south from I-70. It reached 6th Avenue by 1966, Mississippi Avenue by 1970, Parker Road by 1972, and I-25 by 1977. I-225 was widened to three lanes each direction between 6th Avenue and I-70 in the late 1990s. Also the 3-level stack at I-70 was reconstructed about the same time to eliminate left entrances/exits. The City of Aurora fronted money for a new interchange at Alameda Ave , and that opened in Fall 2000. Interchange reconstruction at Parker Road , including adding a loop and a flyover, were completed in Spring 2002. In 2003 improvements where completed at Iliff Avenue which included adding loop ramps.

Construction Timeline

May 1964 Construction of I-225 begins at I-70

June 1966 A one-mile segment of I-225 between Colfax Avenue and East Sixth Avenue opens to traffic.

1969 Bridges at Mississippi Avenue were constructed

September 3, 1971 Another 2.1-miles segment of I-225 opens to traffic between Mississippi Avenue and Parker Road .

May 27, 1975 A two and half mile segment of I-225 between Parker Road and Yosemite Street opens to traffic. Construction begins in 1971.

1976 Bridges at Mississippi Avenue were widened

May 21, 1976 The remaining 1.2 miles of I-225 between Yosemite and I-25 opens to traffic. Costs: 1.6 million; Contractor: Ramsour Brothers, Inc. of Castle Rock, CO

1976 Improvements to the I-225/6th Avenue Interchange Begins Cost: $624,768; Contractor: Peter Kiewit Sons' Co.

July 1990 An overlay project between Parker Road an I-25 begins. Cost: $800,000; Complete: August 1990

August 1990 Replacement of the I-225 bridge over Sand Creek is complete. The new bridge is longer and wider to accommodate future widening. Cost: $4 million

October 1992 Project begins to replace the structures over Smith Road and the Union Pacific Railroad. Also, reconstructs I-225 between Sand Creek (about 30 th Avenue) and Smith Road . Cost: $6.8 million; Contractor: Edward Kramer & Sons, Inc. Complete August 1994

March 1994 The second phase of I-225 and I-70 interchange reconstruction project begins to widen I-225 between Smith Road and I-70. Cost: $4 million; Contractor: SEMA Construction, Co., Inc. Complete: Oct. 1994

April 23, 1994 The new flyover ramp from westbound I-70 to southbound I-225 opens to traffic. $18.2 million project; Contractor: SEMA Construction, Co., Inc; 1,967-foot ramp; 50 feet above I-70; Construction began in March 1993.

April 1995 The projects that reconstructed the ramp from eastbound I-70 to southbound I-225 and the northbound I-225 to eastbound I-70 ramp is completed. Cost: $4 million. Started in Fall 1994

February 1996 Constructs begins to widen I-225 between Colfax Avenue and Sand Creek to six concrete lanes. Cost: $9.8 million; Contractor: SEMA Construction Co., Inc. ( Englewood , CO) Completion: November 1997

July 1996 Construction begins to widen the Mississippi Avenue bridge over I-225. The new bridge will accommodate three through lanes in both directions and two left turn lanes in each direction to get onto I-225. Cost: $5.1 million; Contractor: Edward Kraemer & Sons Complete: May 1998

November 1996 Construction begins to widen I-225 to six lanes between 6 th Avenue and Colfax Avenue . Cost: $5.12 million; Contractor: Castle Rock Construction Co. Complete: December1997

September 1997 The new flyover from northbound I-225 to westbound I-70 opens to traffic. Cost: $7 million; Contractor: Castle Rock Construction Co. Started: March 1997 to Summer 1998

November 1997 Voters approved the construction of a $20 million interchange at I-225 and East Alameda Avenue . I-225 was built in I-225 without an interchange at this location.

February 1998 Construction begins on a sound wall from Parker Road to Yale Avenue on I-225. The project also includes the widening of the bridge over the emergency spillway on Parker Road . Cost: $4.5 million; Contractor: Hamon Contractors, Inc.; Completion: Spring 1999

December 1999 Construction of the second phase of I-225/Alameda interchange project begins. Cost: $12 million; Contractor: Hamon Contractors, Inc.; Completed in March 2001

September 2000 Construction of a flyover ramp from northbound Parker Road to southbound I-225 begins. Cost: $48 million; Contractor: SEMA Construction Co, Inc.

June 2001 Construction begins on the new northbound I-225 off-ramp to Iliff Avenue and a new loop ramp from eastbound Illif Avenue to northbound I-225. Cost: $3.1 million; Contractor: Hamon Contractors, Inc.

2002 New interchange at Alameda and I-225 opens to traffic

April 2003 Construction begins to replace the bridges at 2 nd Avenue and 6 th Avenue over I-225. Cost: $12.3 million; Contractor: Hamon Contractors, Inc. Complete: March 2005

As part of the T-REX project, construction begins to widen I-225 between Parker Road and I-25 to three lanes each direction

CDOT Personnel

Other Contractors:

Economic Impacts

The construction of the new Alameda Avenue interchange was vital to the City of Aurora.