Interstate 45 (I-45): Galveston to Dallas Route, Safety and Bridges

How long is I-45?

The FHWA Route Log, current to January 2026, gives I-45 285.03 miles, every one of them in Texas. Interstate Guide prints the same figure, and Wikipedia's infobox lists 284.91. That makes I-45 the shortest of the main Interstates whose numbers end in 0 or 5; the next shortest, I-30, is 367.28 miles.

The Route Log does not book any I-45 pavement to another Interstate. I-45 does share its lanes with US 190 for 26 miles between Huntsville and Madisonville and with US 287 for 18 miles between Corsicana and Ennis, but those are US highways, so the miles stay with I-45. In Dallas the freeway keeps going past its end at I-30 as unsigned I-345, 1.43 miles that drivers see signed as US 75.

Where I-45 starts and ends

The southern end is on Galveston Island at State Highway 87 and Spur 342, at 61st Street. SH 87 carries traffic on into downtown Galveston. The northern end is at I-30 in Dallas, near Deep Ellum and downtown, where the road continues as I-345 to the Central Expressway.

Northbound, I-45 leaves the island on the Galveston Causeway and passes Texas City, La Marque and League City. It goes by NASA's Johnson Space Center on the Gulf Freeway, curves along the south edge of downtown Houston on the Pierce Elevated and heads north as the North Freeway through Spring, The Woodlands, Conroe and Willis. Beyond Sam Houston National Forest it reaches Huntsville, Madisonville, Centerville, Buffalo, Fairfield, Corsicana and Ennis, then enters Dallas, where it becomes the Julius Schepps Freeway.

Interstate junctions along I-45

Read from Galveston north, the Interstate crossings bunch up at the two big cities. In downtown Houston I-45 meets I-69 (US 59) and then I-10. No other Interstate crosses it between Houston and Dallas. In Dallas it meets I-20 and then ends at I-30.

Fatal crashes on I-45

From 2020 to 2024, 339 crashes on I-45 killed 372 people, about 74 a year. Deaths rose from 68 in 2020 to a high of 80 in 2022, dipped to 73 in 2023 and climbed back to 79 in 2024. Spread over the route's length that is 26.1 deaths per 100 miles each year, almost three times the Interstate average of 9.5. No other route of the 56 we rank comes out higher; I-4 in Florida is second at 25.3.

Because the whole road is in Texas, the useful comparison is between counties. Harris County had 148 deaths, about two in every five. Dallas County followed with 43, then Freestone and Montgomery counties with 33 each and Ellis County with 28.

Counties with the most I-45 crash deaths

Bridges on I-45

The 2025 National Bridge Inventory counts 404 bridges carrying I-45's main line. Four rate Poor, about 1 percent. Most of the rest, 240, rate Fair, and 160 rate Good. The median bridge was built in 1974.

The Pierce Elevated, which forms the south edge of downtown Houston, opened on August 18, 1967. Work on a replacement for the Galveston Causeway began in mid-2003. In Dallas, I-45's elevated section closes during ice storms, and traffic is sent to SH 310 and US 175.

Tolls on I-45

Driving the main lanes from Galveston to Dallas costs nothing. The only tolled pieces in FHWA's January 2023 inventory are two METRO lanes in Houston: the North Freeway HOV/HOT lane from Franklin Street north past Parramatta Lane, and the Gulf Freeway HOV/HOT lane from Bastrop Street and Emancipation Avenue to NASA Road 1. They are the reversible lanes that carry buses and carpools to and from downtown, and a HOT lane also sells space to drivers willing to pay a toll. The 19.9 and 20.9 miles in the table are FHWA's lengths for the two lane facilities, which can run longer than the stretch of I-45 they cover. We found no new toll lanes on I-45 since that inventory.

I-45 auxiliary routes

I-45 has one three-digit route, I-345, and most drivers never see its number. It is the 1.43 miles of elevated freeway that carries traffic from I-45's end at I-30 north to US 75 in Dallas, signed as US 75. I-45's exit numbers keep counting up along it until Spur 366, the Woodall Rodgers Freeway. Its last section, from Lamar Street to the Central Expressway, opened on February 25, 1976.

How I-45 grew from the Gulf Freeway

The oldest part of I-45 predates the Interstate system. The Gulf Freeway between Houston and Galveston was the first freeway in Texas; it opened in stages from October 1, 1948, and reached Galveston on August 2, 1952. The first Interstate contract Texas ever let, in 1956, was for this route in Navarro County, and the federal designation dates to August 14, 1957. The state highway commission approved a 286-mile route in 1962.

In the rural middle of the route, the stretch between Fairfield and Streetman opened on October 13, 1971. Houston added a reversible HOV transitway on the North Freeway on November 23, 1984. During the Hurricane Rita evacuation in 2005, thousands of evacuees jammed I-45 out of Houston and gas stations ran dry. TxDOT reversed lanes starting at FM 1488, but that did not relieve the jam deeper in the city, and four-hour drives took 24 hours.

The next big change is the North Houston Highway Improvement Project. It moves I-45 to run beside I-69 on the east side of downtown Houston and beside I-10 to the north. Harris County sued TxDOT over the plan, which would displace about 1,000 residents, then paused the suit in 2021 to negotiate. A federal civil rights investigation ended in March 2023 with an agreement that let the project go ahead. TxDOT broke ground in October 2024 on a project Equipment World put at $13 billion and about 18 years. The first phase, $121 million of stormwater box culverts, is due in 2027.

I-45 traffic and road conditions

When I-45 is backed up near Conroe or shut at the I-20 interchange in Dallas, DriveTexas has the closure, since it covers the whole route. Houston TranStar adds cameras, travel times and incident reports for the Houston area.

I-45 questions