Police Trial Sound Sensors To Stop Loud Drivers

While loud sports cars may be the interest of car enthusiasts, the vast majority of people dislike loud speeding vehicles that either backfire or use cheap exhausts. To try and tackle the situation, Police in West Yorkshire will trial a new sound camera that will identify noisy individuals. What challenges do loud vehicles present, how will sensor technologies be used to catch loud drivers, and what challenges does sound location present?

What challenges do loud cars present?

Undoubtedly, loud cars can be a serious nuisance to those wanting to live in peace and quiet, but while this could be considered to be somewhat privileged, there are indeed negative effects of loud vehicles. By far, one of the biggest concerns for loud vehicles is that it often correlates with speeding and/or sudden acceleration. It is perfectly possible for a large truck to be loud, but the extreme noise generated by motorbikes and sports cars is often always caused by increased combustion rates. As such, loud cars directly correspond to dangerous driving.

Another cause of concern for loud cars is improper exhaust designs and poor engine performance. It is very common for individuals who want to pretend they have a performance car to make adjustments to their exhaust so that it sounds louder. However, not only does this result in poor performance (via incomplete combustion), but it also increases emission levels.

Finally, cars with modifications to make them sound louder will also frequently backfire. These sounds can well exceed 130dB, which is the equivalent of a gunshot at close range. Such loud pulses of sound not only upset wildlife but can, in fact, cause panic and impaired judgement from other drivers, especially if windows are down and the car backfires adjacent to a driver.

Police testing new sound sensors for catching loud drivers

When it comes to traffic enforcement, the police have numerous tools at their disposal, with vision-based technologies being the most predominant. Speed cameras typically utilise RADAR to determine the speed of a vehicle, and once a speeding offence has been detected, two images are taken to prove the vehicle’s speed. Red light cameras, however, utilise sensors in the road to trigger a camera if a vehicle passes over a red light. Finally, average speed cameras utilise automatic plate recognition and multiple cameras spread out over large distances to calculate the average speed between two points.

However, the sound is something that is rarely (if ever) recorded or used by police, but this is about to change with the introduction of a new sound sensor being deployed in West Yorkshire. One road in West Yorkshire, Fell Lane, has been the centre of discussion with local residents due to excessive vehicle noise. While some blame local car enthusiasts for loud exhausts, others blame a local car dealership specialising in high-end sports vehicles. Regardless of whether the noise is caused by illegal exhausts or sports cars, the local police are now running a £300,000 trial on a new sound camera that aims to put an end to loud vehicles.

After a two-week trial, the camera will then be moved to other locations around the UK (including Birmingham and Gloucestershire) to provide more data on its capabilities. It is hoped that the new sensor will be able to identify vehicles emitting noises greater than 72dB, which is the current legal limit for any road vehicle.

What challenges do sound-based cameras face?

While speed detection and ranging are easy to do thanks to technologies such as RADAR and LiDAR, but trying to detect sound levels and position accurately is another challenge in its own right. 

The first problem that needs to be addressed by such cameras is proving that the source of the loud sound did indeed originate from a specific vehicle. For example, if such a setup uses a singular microphone and camera, then it is likely that a lightning strike will trigger the sensor. As such, at least two microphones will be needed to determine the direction of the sound source. 

The second challenge faced with microphones is accurately measuring the volume generated by a vehicle. As sound is measured in decibels which itself is a logarithmic scale and the intensity of a sound source decreases by 6dB each time the distance from the source doubles, trying to determine the true level is difficult. The challenge that this introduces is not so much technical but more legal. If the technology cannot accurately provide the sound level generated by a vehicle, it could be difficult to use as evidence in a court of law. This is why speed cameras use multiple speed measurement methods. 

Overall, engineers developing sound-based cameras will need to be able to provide accurate position data as well as reliable calibration techniques if fines from loud cars are to be valid. But, even if the cameras cannot be used for fines, they certainly can be used as an intimidation tool by the police. Caught making too much noise? We can’t arrest you, but we certainly can harass you!