Sausage Curbs: A Necessary Evil in Motorsports?

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On April 23, 2023, rookie racecar driver Adam Fitzgerald was competing in the Formula Regional European Championship by Alpine at the Imola Circuit in Italy.

At first, the rookie was in the 25th position, but he was catching up. Just a few laps before the end, he climbed to 22nd position. Suddenly, his race ended when his car spun off at turn two and started gliding through the gravel and grass sideways.

Spin-offs are common in competitive races. However, Fitzgerald's right rear tire hit a curb by the side of the road, launching him roughly one meter in the air. His race car smashed onto the track. The accident left him with three fractured vertebrae, forcing him to take a month-long break from his season.

After the event, Fitzgerald's team published an Instagram post in which they called for the removal of "Sausage Kerbs" from race tracks, joining a number of car racing professionals who have openly criticized the curbs due to safety concerns.

"Cars can pop up, do big wheelies, and then slam back down again, which can be very painful on the back," McLaren F1 driver Lando Norris wrote in his column for The Telegraph last July. He was responding to Henrique Chaves' crash in Monza, where his Aston Martin landed upside down after being launched into the air by a similar kerb.

What is a "Sausage Kerb"?

Car racers call them "sausage kerbs." They are a part of the kerbs even higher than the other parts of the curb to discourage drivers from driving over them. They can be made of concrete, metal, or plastic. Each racetrack has its own specifications for these kerbs, but most of them are painted with red or yellow paint to warn drivers to keep away.

Sausage kerbs were introduced just over a decade ago. Following the introduction of a concrete buffer zone that enabled racecar drivers to drive off-track without the need to slow down, drivers began taking advantage of the new feature, pushing their vehicles further onto the edge of the racetrack.

Rising above the ground clearance of many racecars, the kerb has been caught in a constant controversy over whether it is a safety hazard for drivers.

In 2018, the Yas Marina Circuit in Abu Dhabi installed a sausage kerb 50mm high by the exit of turn 20. The kerb had to be repaired by the following day after its debut during the practice day of the Abu Dhabi Grand Prix. The kerb scratched the bottoms of F1 cars that ran over it.

The F1 race cars participating in the 2023 races have a ground clearance of no less than 45mm. However, race teams and drivers can choose to raise their car's ground clearance, even though a higher ground clearance can sacrifice downforce.

Are the kerbs effective?

Despite the incidents, sausage kerbs remain a common feature on many racetracks. While the FIA has not issued specific regulations on where and what type of kerbs should be installed, race tracks make their own decisions based on their individual circumstances.

Sausage kerbs are effective in deterring drivers from driving off the track to gain advantages, but the FIA is unclear on how penalties should be issued to those who do. The current guidance states that drivers must make every effort to stay on the track and cannot leave it without a justifiable reason. If they do leave the track, they may return safely and without gaining a lasting advantage. However, there is no clear definition of what constitutes driving off track or what is considered an advantage.

The ambiguity surrounding penalties for driving off track is due in part to the fact that it is only in recent years that doing so has become advantageous for racers. In traditional racetracks, grass and gravel traps are used in the run-off areas, which can help to slow down the driver and provide friction to prevent them from losing control. However, modern racetracks have extended their tarmac surfaces deeper into the run-off area, reducing the consequences for drivers who push the limits of the track. This can allow them to cut closer to the edge of the track when going through the apex, potentially giving them an advantage.

While the FIA may order drivers to give back any space gained by going off track, penalties are also possible if this is not feasible. For example, in the 2012 German Grand Prix, Vettel received a 20-second penalty for driving outside of the racetrack for a longer straight line during takeoff. However, records of similar penalties were incomplete until 2014, and most were issued after 2019. In fact, nine out of the 36 documented cases were issued in 2022, suggesting that the FIA is taking a tougher stance on the issue.

Interestingly, one in seven penalties were issued at the Circuit of the Americas (COTA), followed by the Sochi Autodrom. Both circuits have sausage kerbs installed next to corners where drivers commonly cut through to gain an advantage. COTA installed two new kerbs at turn 17 in 2018 in response to Verstappen's off-limit takeoff in 2017. These kerbs are reported to be two meters long and 50mm tall.

However, three years later, UK driver Abbie Eaton suffered a fractured vertebra when her vehicle bounced over one of the kerbs during a W-Series competition. The front wheels of her F3 race car lifted, and the car landed back on the ground heavily due to gravity.

As a response to the incident, COTA removed five of its kerbs for the 2022 season. At the same time, the FIA imposed stricter penalty rules during the race, resulting in three off-track penalties being handed out during the 2022 race. The first two penalties were issued in 2016 and 2017, respectively.

Things we don’t know about the kerbs

Tracking all injuries and accidents caused by sausage kerbs is not a straightforward task due to their use across multiple racing series.

In 2015, the FIA began building the World Accident Database (WADB), which records all injuries and fatalities in all FIA-regulated motorsport events. However, this record is not accessible to the public, citing personal medical record privacy concerns.

The lack of data makes it challenging for parties outside of the FIA to determine whether sausage kerbs are a necessary evil or a safety hazard that needs to be addressed.