June
2013
|
Interstate
10 and Texas State Highway 105 provide useful insight into ensuring that
highways meet regional transportation needs. |
Anyone who has driven down a highway and grumbled about incoming traffic, gridlock, and other issues recognizes that some highways are more useful than others for medium-distance travel. Carrying capacity, safety, access, and other issues must be addressed over the entire lifecycle of a highway to maintain and enhance its efficacy.
In the United States, urban planners must address such problems in the face of budget shortfalls. Specific case studies with respect to what went right and wrong are essential to meet this goal.
Meeting this need, Yingfeng Li (Texas Transportation Institute, San Antonio) and coworkers have recently provided an analysis of two Texas highways, the Katy Freeway in Houston and Texas State Highway 105 between Conroe and Montgomery. In brief, the Katy Highway is a lesson in how to develop a nationally acclaimed highway, and Texas State Highway 105 is a lesson in how a highway can badly deteriorate on a functional level.
Katy Highway: Houston
The Katy Freeway has (in both directions) two high-occupancy toll lanes (managed lanes), four general-purpose lanes, and three frontage road lanes. Its latest expansion was completed in 2009 thanks to interagency collaboration, and the scientists’ analysis focuses on an 11.5-mile section within the Houston city limits.
Beginning in the 1970s, this section of the Katy Freeway began to lose its functionality because of continual commercial development along the road. Traffic volume increased by a factor of four from the mid-1960s to the 1990s, and maintenance costs and crash rates respectively reached four times and 33% more than that of similar Texas highways.
Initial efforts to improve the highway included a reversible-direction, high-occupancy vehicle lane in the 1980s. Although effective and valued by motorists (it reduced traffic congestion on the rest of the highway), commercial development and a railroad along the highway hindered further highway development.
Urban planners were eventually able to purchase the rail line and its right-of-way. Highway improvement began in 1995.
The managed lanes (free of charge to city buses, but often has a toll for other users) were designed such that they could be converted into light rail in the future, and the pavement was designed to have a lifetime of 30 years with minimal maintenance. The Texas Department of Transportation successfully instituted financial incentives to the highway contractors to complete the project on time.
Intersecting street overpasses, u-turn lanes, and traffic management technology help manage traffic flow and alert road users to problems. The managed lanes work well in that the average speed is over 60 miles per hour in most locations.
Texas State Highway 105: Montgomery County
In contrast with Houston and the Katy Freeway, Texas State Highway 105 continues to functionally deteriorate. This highway, completed in the 1960s, has seen a large increase in traffic since the construction of Lake Conroe in the early 1970s and the concomitant development of what was once an agricultural area.
In the 1960s, traffic was around 2,000 vehicles per day. In 2005, traffic was at 30,000 vehicles per day.
Although the highway was widened in the mid-1990s, it has lost much of its original functionality. For example, the 20.9-mile study section has on average 24.6 access points per mile, over 86% of which are private streets (e.g., to residences and businesses), and there are few off-highway access points to and connections between these streets.
There are 14 signalized access points, but they are not coordinated with each other. The crash rate has also increased along the highway, commonly to 100 crashes per year from 2003–2009, more than six times the per-mile Texas rural highway crash rate.
Montgomery County is currently unable to address these problems because it has no authority to regulate land use. Meanwhile, the city of Conroe chooses to not review proposed development along the highway, although state law allows it to do so.
The city of Conroe has neither access, zoning, nor sign ordinances, although it does regulate landscaping and vehicle parking. They have chosen to essentially not cooperate with Texas state agencies with respect to highway management, and the city currently does not have a reasonable long-term traffic management plan for Texas State Highway 105.
Implications
Li and coworkers’ take-home message is that long-term planning can pay important dividends, and unchecked local development can severely disrupt highway functionality.
Interagency collaboration has allowed Houston to greatly improve the Katy Freeway. The city of Conroe could greatly improve Texas State Highway 105 by taking reasonable measures such as collaborating with knowledgeable state agencies, reducing highway access points, upgrading signalized access points, and constructing parallel roads for local traffic.
NOTE: No funding is specifically noted for the authors’ research, but my best guess is that it was funded by the Texas Department of Transportation.
For more information:
Li, Y; Hard, E. N.; Bochner, B. S. “Planning actions to preserve and enhance highway functionality–Case studies.” J. Urban Plann. Dev., 2013, in press. DOI: http://dx.doi.org/10.1061/(ASCE)UP.1943-5444.0000143