The Southwest Freeway in Midtown Houston, Texas’ second busiest highway at 313,000 mvt/day.
see List of busiest roads in Houston.
In 2013, the Katy Freeway (I-10) east of the Beltway 8 interchange was Houston’s busiest point with 383,000 vehicles per day. At the time, this was also the second busiest highway in the United States.
According to medicinelearners, congestion is one of the biggest issues in the Houston area, a result of the explosive population growth. Congestion is most intense on freeways that have not expanded substantially since opening, especially the notorious ‘West Loop’ (I-610) through Uptown Houston, which has traffic jams almost all day. Because a lot of commuter traffic over the last kilometers is handled via the frontage roads, also known locally as “feeders”, traffic jams do not quickly affect the highway network. Many driveways also have dosing lights to control the supply to the highway. In practice, through traffic will not use the ring roads, but will simply drive through the center, because the ring roads are relatively far around, that certainly applies to the toll ring roads. Moreover, the conurbation is so large that a complete ring road around it would soon be about 300 kilometers long.
There are residential areas that are more than 10 kilometers from a highway, which can cause local roads to be busy as well. One of the advantages of the lack of a strict spatial planning policy is that commuter traffic is not only aimed at the center, but also at the many industrial estates and office parks on the edge of the agglomeration or along the ring roads. In addition to the center, Houston has another high-rise center 10 kilometers west of the center, which is called Uptown. Major employers such as the Texas Medical Center, NASA and the petrochemical industry are all a bit further from the center. There are also large industrial estates along the various radiating highways. The Woodlands 40 kilometers north of the center has become an important work location and has the characteristics of an edge city.
Between 1982 and 1986, vehicle miles traveled (VMT) increased by 23.4%, but lane kilometers increased by only 15.5%. The result was congestion growth of 37% (expressed in the travel time index). Between 1986 and 1993, the number of lane kilometers increased by 35.9% and the number of VMT by 25.6%, resulting in a 35% decrease in congestion. Houston was the only major conurbation since the 1960s where congestion has eased. This shows that road widening can result in less congestion, also with an increase in traffic. However, Houston continued to grow very fast, between 1993 and 2007 the VMT increased by 54.8%, more than the number of lane kilometers (17.2%). The result was another growth in congestion, by 94%.
Traffic growth is not the same everywhere. The strongest growth in traffic is in the west and north of the agglomeration, especially in the region between 10 and 40 kilometers from the center. Traffic growth in the 10 kilometers around the center (within I-610) is small. In the southeastern quadrant of the metropolitan area, traffic growth is small, and at times also slows due to changing demographics and job relocation to the suburbs west and north of Houston.
There is also an interaction with traffic growth. As the Katy Freeway (I-10) widened through western Houston, intensities decreased on the Southwest Freeway (I-69) and Northwest Freeway (US 290), as well as on the Westpark Tollway and FM 1093 (Westheimer Road).. Also on the North Freeway (I-45), the intensities on the first 20 kilometers from the center have decreased as the Sam Houston Beltway was completed in northeast Houston.
A striking development is the strong growth in employment around The Woodlands and Spring in the north of the conurbation, 40 kilometers north of the center. This has been the case especially since the 1990s. The most accessible highway to this area is the North Freeway. Originally, there was a strong rush hour direction to and from the center, and an alternating lane constructed on the North Freeway. However, with the growth of employment in The Woodlands and Spring, such a strong traffic flow has developed that there is just as much traffic ‘outbound’ in the morning rush hour as the traditional ‘inbound’ rush hour direction to the center. It is therefore planned to replace the alternating lane with four toll lanes, two in each direction, because there is no longer a dominant rush hour direction.
Employment growth is increasingly occurring in the suburbs. As a result, the demand for circular connections (ring roads) around the agglomeration increased. The first beltway, I-610, was around the city in the 1960s. 10 to 15 kilometers further out, the Beltway 8 was built in the 1980s and 1990s. At the time, Houston was growing very fast and the continuous urbanization was soon far beyond Beltway 8, which by American standards is already quite a long beltway, it was already longer than the beltway around Washington, D.C. Today, the area of Houston outside Beltway 8 is larger then enter it and the SH becomes 99 developed as (provisional?) outer ring road. Houston is the first American city to have three beltways. And suburban area, especially on the north side of Houston, is up to 20 miles off SH 99.
Due to the rapid urban expansion outside Beltway 8, traffic on this ring road increased faster than expected. Within 10 years, parts have been widened from 2×2 to 2×4 lanes. The ring roads are also further and further apart. I-610 is just 8 to 11 miles outside of downtown. Beltway 8 was already 20 to 25 kilometers outside the center and SH 99 is 35 to 50 kilometers outside the center. Already in the first year of opening of SH 99 along Houston’s west side, there were indications that it may be undersized with only 2×2 lanes.
|Travel time to work|
|Harris County||27.4 minutes|
|Montgomery County||31.7 minutes|
|Fort Bend County||30.6 minutes|
|Brazoria County||28.8 minutes|
|Galveston County||26.7 minutes|