By Kristin Dispenza

Ever wonder what it would take for four local governments whose villages abut the world's widest freeway to solve noise-abatement problems? Here is that story.

Four Texas villages straddle the portion of Interstate 10 known as Katy Freeway, which has 26 lanes in some spots. They are Hunters Creek Village (population 4,400, Tom Fullen, city administrator); Hedwig Village (population 2,500, Kelly Johnson, city administrator); Spring Valley Village (population 4,013, Julie Robinson, city administrator); and Hilshire Village (population 746, Susan Blevins, city administrator).

Katy Freeway runs from the downtown Houston area westward for approximately 23 miles to the suburb of Katy. It is a major thoroughfare that connects Florida to California. Near Hunters Creek Village, it is currently 16 lanes wide, including service roads.

When originally constructed in the 1960s, the highway was comparatively narrow, but as the local population grew and a greater number of people used the road for interstate travel, congestion became a problem. The Texas Department of Transportation (TxDOT) reconstructed the freeway between 2003 and 2009, widening the road and redesigning its on-off ramps to improve flow.

Nine major construction contracts were awarded and every contract stipulated a maximum number of hours that a lane of traffic could be closed during peak travel periods each day.

Noise Problems Emerge

Congestion may have been an issue on the pre-2009 roadway, but at least noise was not. When the new lanes opened, however, less congestion meant that 60- to 70-miles-per-hour highway speeds were possible, and the faster moving vehicles generated significant tire-pavement interface noise.

Transverse tining, in which a textured surface is installed with a set of randomly spaced spring steel tines in a direction perpendicular to the centerline of pavement, was the preferred surface texture at the time of construction, long considered a safe and durable means of providing traction.

Transverse tining, unfortunately, is also one of the loudest surface textures available. With the increase in traffic and speed, the surrounding neighborhoods were overwhelmed with the incessant drone of tire-pavement noise.

This meant that a significant length of the reconstructed highway suddenly had a noise problem. Many of the properties adjacent to that stretch were commercial or retail and were not particularly sensitive to noise.

The four- to five-mile section that is flanked by residential villages, including Hunters Creek to the immediate south, however, were hard hit. Residents of the villages expressed that they had never heard road noise levels so high, and the noise wasn't just bad at certain times of the day, it was nearly constant.

Environments with excessive noise aren't merely annoying. They're considered a health hazard, with documented effects on individuals that include sleep disruption, impaired function, and reduced productivity. Residents took their concerns to elected and appointed officials, who took it upon themselves to address the matter.

Quantifying the Problem

Officials representing the affected villages approached TxDOT hoping to have noise abatement procedures implemented. They were told that TxDOT had closed out the project and had no additional funds to address noise, as funding is typically allocated years in advance of a project.

The department also had conducted modeling during the design phase that indicated the road was in compliance with federal noise standards.

One point that Hunters Creek Village representatives noted was that the original highway design parameters for the widening of Katy Freeway did not reflect the as-built road because of the number of change orders, design modifications due to failed land acquisitions, easements, and so on.

These challenges are particularly numerous in densely populated areas, and they cause noise modeling conducted prior to the start of construction to inadequately forecast finished conditions.

Two of the communities commissioned their own noise tests, hiring the same contractor and using the same software that TxDOT had used when conducting its research in order to compare test results. The same instruments and the same placements also were used, and tests were conducted at the same time of the year.

The new tests conducted with live traffic showed the road to be considerably out of compliance with federal noise standards. The new noise tests—totaling two tests in two different locations—were conducted in October 2010.

Armed with the results, officials of the residential villages spent the next several years pursuing a solution to their communities' noise problem.

Seeking a Solution

The communities' first resource was their local congressman who was responsible for getting the Katy Freeway expansion completed without any earmarks at the federal level. Attempts to have the project reopened and the noise levels corrected with this channel proved extremely challenging.

Next, the state representative was contacted, who followed up by meeting with residents from either side of the freeway. That representative then put the villages in contact with TxDOT's director of transportation.

The villages expressed interest in rubberized asphalt, which was considered one way of addressing road noise. TxDOT experts pointed out that this type of asphalt is not only expensive, but because of its porous nature and air-void content, it tends to compress and consolidate, losing its noise dampening qualities with time and traffic.

To avoid this deterioration, the rubberized asphalt would have required maintenance every several years, defeating the purpose of using long-life concrete pavement in the first place. Such a maintenance-intensive solution was off the table from the start.

TxDOT had an alternative proposal, suggesting a project that involved first removing transverse grooves from the roadway, then replacing them with a diamond saw-cut concrete surface texture known as the Next Generation Concrete Surface (NGCS).

At this point, the International Grooving & Grinding Association (IGGA; www.igga.net) was brought in to discuss the proposal with TxDOT. After inspecting the freeway and viewing the data, IGGA was certain that NGCS would significantly reduce the tire-pavement noise issue without the need for reoccurring maintenance, while also providing a safe, smooth driving surface.

Developed by IGGA and the American Concrete Pavement Association at Purdue University between 2006 and 2008, the NGCS surface can be installed using conventional diamond grinding equipment, with the first step being to flush-grind the concrete and then to cut longitudinal grooves for a smoother and flatter surface.

Finding the Money

The cost of this project was approximately $12.5 million, including traffic control. Because about half of the affected roadway was within village jurisdictions and half was within the city of Houston, TxDOT proposed that Houston and the four affected villages contribute approximately $2 million of that total cost. Each village was asked to make five installment payments to TxDOT over a five-year period with no interest charged.

The communities agreed to TxDOT's terms, but raising the funds took another two years. The four villages were able to get the money into their annual budgets, but Houston was slowed by two concerns.

The first centered on how to proportionally allocate funds across its entire road network, a common consideration for road owners. The second concern dealt with a newer type of challenge: the legalities of a city contributing local funds to a federal road. Houston's city councilman and city attorney examined this matter for some time.

Factoring into their decision was a precedent in Harris County where homes backing the freeway had successfully argued down their tax values on an annual basis, based on the fact that an excess of noise was reducing their property value. The homes in Hunters Creek Village—which represent a majority of all building types in the village—were valued in excess of $2 billion. The local governments realized they faced a reduction in a property tax basis as property values fell.

Fast forward: Funding from TxDOT, Houston, and four villages was eventually secured and in 2016, the project was let for bid. Transverse tining was removed and NGCS installed, with construction completed by fall 2017.

Residents were quick to express their contentment with the new surface. The noise abatement was significant.

The Future

According to Hunters Creek Village officials, another consideration that local government officials need to address early on is the possible insufficiency of sound walls. In the 2009 reconstruction of I-10, for example, the presence of biosystems and waterways parallel to the freeway were points of interference that caused gaps to be left in the wall layout.

Acoustic engineers hired by the affected villages during their noise analysis process discovered that these gaps actually amplified and intensified road noise. The impracticality of positioning walls in the precise locations necessary to interrupt sound waves was also suspected of compromising the functionality of the wall system. In addition to issues with their effectiveness, the installation and maintenance of sound walls is expensive.

Experts anticipate that the amount of money required for road building and maintenance will continue to dramatically outstrip federal revenue that is raised to conduct the work. Local officials will likely find themselves responding to residents' inquiries and will have to develop mechanisms for the future funding of roads of all types, even those that have traditionally been paid for by federal sources.

Kristin Dispenza is account manager, Advancing Organizational Excellence (AOE), Detroit, Michigan (Kristin.dispenza@theaoeteam.com).