In cities where cyclists are becoming more common—and urban soundscapes more complex—one of the most basic safety tools may have just received an important upgrade.
Automaker Škoda, in collaboration with University of Salford, has unveiled the Škoda DuoBell, a redesigned bicycle bell engineered specifically to cut through noise-cancelling headphones. The innovation addresses a growing and often overlooked safety issue: pedestrians simply not hearing cyclists approaching.
A Modern Problem Meets an Analogue Solution
As active transportation rises in major cities—London, for instance, is expected to see cyclists outnumber drivers this year—so too have conflicts between cyclists and pedestrians. According to Transport for London data, bike–pedestrian collisions rose by 24% in 2024. One factor not often considered is the popularity of Active Noise Cancellation (ANC) headphones, which can filter out everyday warning sounds, including traditional bike bells.
Rather than turning to digital fixes, Škoda’s answer is surprisingly analogue: a mechanical bell that “outsmarts” ANC algorithms.
The DuoBell uses carefully engineered acoustics to ensure it gets heard—even when listeners are intentionally blocking out the world.
The Science Behind the Sound
Researchers at the University of Salford conducted one of the first studies into how ANC technology affects the audibility of bike bells. They discovered a narrow frequency band—between 750Hz and 780Hz—that consistently slips through noise-cancelling filters. This “safety gap” became the foundation of the DuoBell’s design.
The bell incorporates:
- A resonator tuned to that critical frequency range
- A second resonator at a higher frequency
- A striking mechanism that produces irregular, unpredictable impacts
Together, these elements generate sound waves that ANC systems struggle to cancel, allowing the bell to reach listeners more effectively.
Skoda DuoBell
Earlier Warnings, Safer Streets
In controlled testing, the results were significant. Compared to a standard bell, the DuoBell could be heard:
- Up to 5 seconds earlier
- At distances up to 22 metres farther
That added reaction time can be crucial in dense urban environments, giving both pedestrians and cyclists a better chance to avoid collisions.
The bell was also tested in real-world conditions through a two-week trial with delivery riders from Deliveroo. Their feedback helped refine the final prototype. One rider summed up the impact simply, saying the bell gave him “a voice in the streets.”
Open-Source for Wider Impact
Škoda has also released all the research as an open-source whitepaper, which means that other manufacturers can adopt and build on the findings. The goal is not just to introduce a single product, but to establish a new standard for audible safety in cities.
An awareness campaign is also underway, featuring mathematician and broadcaster Hannah Fry alongside cycling-focused creators, aiming to highlight the issue across social platforms.
As cities continue to evolve, the humble bike bell—long unchanged—may once again become a critical piece of urban safety infrastructure.