Texas State Highway 99

Segment A is a segment that would extend from SH 146 to I-45 South. It is currently not considered a viable project.[7]

Segment B Construction has not yet begun.[8] This segment extends from I-45 South to SH 288.

Segment C Construction has not yet begun.[9] This segment extends from SH 288 to I-69/US 59 South.

Segment D, the first section opened, runs from just north of Interstate 10/US 90, west of Houston, south to Interstate 69/US 59 in Sugar Land where it terminates and intersects with FM 2759. The portion of this segment south of the interchange with the Westpark Tollway is now a four-lane divided highway feeder road, with maintains crossing over the Westpark Tollway.

The 18-month-long construction of two ramps connecting westbound I-10/US 90 to southbound SH-99 and northbound SH-99 to eastbound I-10/US 90 was completed in 2011. The occasional traffic jams at this intersection prompted the sped-up construction of the ramps before the through lanes of SH-99 were built through the I-10/US 90 interchange. Two more ramps connecting southbound SH-99 to eastbound I-10/US 90 and westbound I-10/US 90 to northbound SH-99 opened as part of the construction of Segment E in December 2013. A final ramp connecting northbound SH-99 to westbound I-10/US 90 has been completed and is operational.

Between the Westpark Tollway and I-69/US 59, Fort Bend County has constructed toll overpasses at nine locations along Highway 99. Motorists are charged around 35¢ to use each overpass, or can bypass the toll by using the current roadway through the signalized intersections.[11] Overpasses between I-69/US 59 and US 90-Alt opened on February 27, 2014, Airport Boulevard and Harlem Road on March 18, 2014, and Mason Road and Bellfort Street on March 30, 2014. The rest of the tolled overpasses to I-10/US 90 opened in late April 2014.[12]

A TXDOT study is currently underway for Segment D of the Grand Parkway.[13] The study includes looking at ways to reduce traffic in the original segment of the non-tolled portion of the freeway; this includes the possibility of adding continuous feeder roads. This segment has been open since 1994 and population, and thus traffic, in the surrounding area has increased exponentially. There is no timetable on when or if any new projects will come out of this study.

September 2011 construction began on Segment E connecting I-10/US 90 Katy Freeway in the south to US 290/SH 6 and opened in December 2013. On June 3, 2008, the Harris County Commissioners Court voted to fast track the construction of Segment E with construction to begin in 2009 and then came the addition of $150 million in Stimulus money yet still the project stalled. As with many Stimulus projects it turned out not to be "shovel ready" enough and the $150 million was sent back to TXDOT for use elsewhere.[14] In 2011 the Wetlands permit from the Army Corps of Engineers was acquired. In addition, Harris County relinquishing its rights to TXDOT who will construct a Public Private Cooperative toll road. At its April 28, 2011 meeting TXDOT allocated $350 million and the construction permits were let in July 2011.[14] On July 28, 2011 TXDOT reported that three out of four contracts for Segment E were awarded and that construction would start by early September 2011.[15]

The multi year reconstruction of I-10/US 90 was completed in 2008 while US 290/SH 6 reconstruction was not due to even start until 2011. "[16] The 22-mile (35 km) long section of I-10/US 90 from the suburb town of Katy to just inside the I-610 loop has expanded it to handle the rapidly expanding western suburbs of Houston not just adding lanes, but also an expanded HOV with two lanes in both directions where there was one lane reversed back and forth with rush hour and a toll lane for commuters willing to pay congestion prices for the quicker ride. The idea put forth is that Segment E is toll-viable from the start meaning it would pay for itself with tolls collected because of the need to relieve traffic on US 290/SH 6 along with the continued expansion of the western suburbs. After US 290/SH 6 construction is completed and less traffic is diverting down the E Segment of the Grand Parkway; the reasoning is that the inevitable population explosion going on in the area would not just replace the lost traffic from the US 290/SH 6 completion, but increase its use.

Segment F-1 connects US 290/SH 6 to Texas State Highway 249. Construction began June 2013 and was completed and opened to traffic on February 5, 2016.[17][18]

Segment F-2 connects Texas State Highway 249 with I-45. Construction began on Segment F-2 in June 2013. A one-mile section of frontage road lanes between I-45 and Holzwarth Road (near the ExxonMobil Campus in Spring) was completed and opened to traffic in April 2015. The remainder of Segment F-2 opened on February 5, 2016.[19][18]

Segment G connects I-45 with I-69/US 59 North. Construction began June 2013 and was completed and opened to traffic on March 29, 2016. An interchange with the Hardy Toll Road to the Grand Parkway was completed on July 18, 2016.[14][17][20]

Texas Transportation Commission members met in Pasadena in late June 2015, and one item on their agenda is soliciting interested builders to develop, build and maintain the next 37.4 mi (60.2 km) Grand Parkway segment from Interstate 69/US 59 north of Houston to Interstate 10 east of the city. The project, which began construction in the summer of 2017,[10] is expected to cost $1.2 billion. The completion date was delayed from 2019 to the spring of 2022 due to Hurricane Harvey.

The southern end of the tolled portion of segment I-2

Segment I-2, which opened on March 25, 2008, after five years of construction, runs from Interstate 10 east of Houston south to Business State Highway 146 in Baytown. (The former Spur 55, which ran from FM 1405 to Business 146, was renumbered SH 99 and connects with the newly constructed portion of Segment I-2 at FM 1405.)

TxDOT began collecting tolls on this segment on November 1, 2011. Motorists are able to pay tolls using any of the Texas toll tag transponders (TxTag, EZ TAG or TollTag), the K-Tag (Kansas) or the Pike Pass (Oklahoma). No cash or mail payments are available on this segment. Tag reader gantries have been installed on the mainline just south of FM 565, and on the northbound entrance and southbound exit ramps at FM 565. Tolls will be $1 for two-axle vehicles.[21]