The Circuit of The Americas in Austin is one of Formula 1’s most popular venues thanks to its layout, but it is also one of the most difficult circuits to keep completely smooth. The recurring bumps at COTA are not simply the result of asphalt wear. Beneath the racing surface lies clay-rich soil that is sensitive to changes in moisture, allowing the ground to move and gradually creating new depressions and uneven sections.
Maintenance work has repeatedly attempted to control the problem through resurfacing, localised reinforcement and increasingly precise methods of identifying damaged areas. Yet despite the repairs carried out over the years, the bumps remain one of the most frequently discussed characteristics of the United States Grand Prix at Austin.
For Formula 1 cars, particularly those designed around ground-effect aerodynamics, this is about much more than driver comfort. An uneven track surface can affect aerodynamic performance, underfloor wear and the stability of the car at high speed.
Circuit of The Americas: Why clay-rich soil causes recurring bumps
The Circuit of The Americas, which opened in 2012, was built in an area where the ground can change volume depending on its water content. This characteristic is especially important when considering the long-term stability of the racing surface.
Expansive clays tend to swell when they absorb moisture and shrink during drier periods. These movements can cause differential settlement and deformation of the surface, particularly when they affect large areas subjected to repeated loads.
On an ordinary stretch of road, relatively small changes in surface level may barely be noticeable. On a racing circuit designed for single-seater cars negotiating high-speed corners and heavy braking zones, however, even relatively minor surface irregularities can have significant consequences.
This is the fundamental challenge facing COTA: maintaining a smooth racing surface while the ground beneath it continues to move.
Why Austin’s bumps are a problem for Formula 1 cars
Drivers have repeatedly criticised the uneven sections of the Circuit of The Americas. Their concerns are not limited to the physical sensations experienced behind the wheel, but also involve the ability of their cars to maintain consistent contact with the asphalt.
Modern Formula 1 cars use their floors to generate a substantial proportion of their aerodynamic downforce. To exploit this principle effectively, they must maintain a ride height that allows the underfloor aerodynamics to operate within their intended performance window.
When a car encounters a bump at high speed, the suspension must absorb the impact without excessively compromising control of the aerodynamic platform. This creates an additional challenge for engineers when selecting the suspension settings and ride height needed to balance performance with stability.
If the floor repeatedly makes contact with the asphalt, plank wear, structural loads and aerodynamic load fluctuations can increase. Under certain conditions, surface irregularities can also intensify bouncing or cause the car to become less stable.
It is important, however, to distinguish these effects from aerodynamic porpoising in the strict sense. Not every bouncing movement caused by a bump is aerodynamic porpoising. The two phenomena can influence one another, but they have different underlying causes.
This distinction matters when assessing car performance at Austin, where teams must manage both the physical characteristics of the track surface and the aerodynamic behaviour of their cars. Ferrari’s Austin FP1 technical analysis of the SF-26 provides further context on the demands of the circuit and the different performance characteristics exposed during practice.
The 2022 repairs: New asphalt and concrete reinforcement
To address the recurring surface problems, the Circuit of The Americas has undertaken several maintenance and redevelopment projects over the years.
In January 2022, the circuit completed another phase of work, using ground-penetrating radar and laser-mapping systems to identify areas requiring specific repairs. These technologies allowed engineers to examine the condition of the track and determine where different types of intervention were necessary.
The programme included resurfacing Turns 12 to 16 and installing concrete slabs to reinforce the areas around Turns 2 and 10. The objective was to strengthen the structure locally while improving the condition of the racing surface.
The decision to use different solutions in different sections followed a clear technical rationale. Not every part of the circuit experiences the same problems, and not every affected area necessarily requires the same type of repair.
Where the problem is concentrated in a relatively limited area, localised reinforcement can help improve stability. Where the surface is deteriorating or suffering from more widespread irregularities, direct resurfacing may instead be required.
Austin’s major 2024 resurfacing: More than 18,000 tonnes of asphalt
The work carried out in 2022 did not permanently eliminate the circuit’s surface problems. In 2024, COTA therefore completed another, more extensive resurfacing programme divided into two phases.
According to information released by the circuit, more than 18,076 tonnes of asphalt were used. The first phase was completed before the MotoGP Grand Prix of the Americas in the spring, while the second was finished ahead of the World Endurance Championship event in September.
The scale of the operation demonstrates how much work has been required to maintain the surface of one of Formula 1’s most distinctive venues. However, the underlying difficulty remains the nature of the ground on which the circuit was constructed. As long as the clay-rich soil continues to expand and contract with changes in moisture, keeping the asphalt consistently smooth presents an ongoing engineering challenge.
For Formula 1 teams, the condition of the surface is another factor to consider when preparing for the United States Grand Prix. Alongside aerodynamic balance and ride height, the interaction between the tyres and the asphalt remains important, particularly at a venue where the track surface has undergone repeated changes. The characteristics of the asphalt are also relevant to the tyre and strategy considerations identified by Pirelli for Austin.
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