Interstate 45

Interstate 45
I-45 highlighted in red
Route information
Maintained by TxDOT
Length	284.91 mi[1] (458.52 km)
Existed	1971–present
NHS	Entire route
Major junctions
South end	SH 87 / Spur 342 in Galveston
Major intersections	I-610 in Houston US 90 Alt. in Houston I-69 / US 59 in Houston I-10 / US 90 in Houston US 190 from Huntsville to Madisonville US 79 in Buffalo US 84 in Fairfield US 287 from Corsicana to Ennis I-20 in Dallas US 175 in Dallas
North end	I-30 / I-345 / US 67 in Dallas
Location
Country	United States
State	Texas
Counties	Galveston, Harris, Montgomery, Walker, Madison, Leon, Freestone, Navarro, Ellis, Dallas
Highway system
Interstate Highway System Main Auxiliary Suffixed Business Future Highways in Texas Interstate US State Former Toll Loops Spurs FM/RM Park Rec
← SH 44 → SH 45

Interstate 45 (I-45^[a]) is a major Interstate Highway located entirely within the U.S. state of Texas. While most primary Interstate routes which have numbers ending in "5" are cross-country north–south routes, I-45 is comparatively short, with the entire route located within Texas. Additionally, it has the shortest length of all the primary Interstates divisible by 5, and the only intrastate Interstate Highway of such. It connects the cities of Dallas and Houston, continuing southeast from Houston to Galveston over the Galveston Causeway to the Gulf of Mexico.

I-45 replaced U.S. Highway 75 (US 75) over its entire length, although portions of US 75 remained parallel to I-45 until its elimination south of Downtown Dallas in 1987. At the south end of I-45, State Highway 87 (SH 87, formerly part of US 75) continues into downtown Galveston. The north end is at I-30 in Downtown Dallas, where US 75 used the Good-Latimer Expressway. A short continuation, known by traffic reporters as the I-45 overhead,^[3] signed as part of US 75 and also part of unsigned I-345, continues north to the merge with the current end of US 75. Traffic can use Spur 366 (better known locally as the Woodall Rodgers Freeway) to connect to I-35E at the north end of I-345.

The portion of I-45 between Downtown and Galveston is known to Houston residents as the Gulf Freeway. The short elevated section of I-45, which forms the southern boundary of Downtown, is known as the Pierce Elevated after the surface street next to which the freeway runs, while north of I-10 it is known as the North Freeway. I-45 and I-345 in the Dallas area, north of the interchanges with I-20 and SH 310 (old US 75), is the Julius Schepps Freeway. The Gulf Freeway and North Freeway both include reversible high-occupancy vehicle lane (HOV lanes) for busses and other HOVs to and from Downtown.

The freeway is the subject of ongoing controversy and federal investigation due to a proposed expansion project in Harris County, which would displace hundreds of people from their homes and worsen air quality.^[4] The local authorities have opposed the expansion project, while the Texas Department of Transportation (TxDOT) supports expansion, and negotiations are pending.^[5][6] The project's estimated cost is at least $9.7 billion and is expected to take at least two decades to complete.^[7][8]

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