The art of noise... the sound of silence

The connection between traffic speeds and accidents is well documented. Research shows that one in three road deaths is speed related, and even a 1 mph reduction can equate to a five percent decrease in the number of accidents resulting in injury.

However, traditional traffic calming surfaces not only create noise and inconvenience for speeding drivers, but also for anyone in the immediate vicinity. That’s why Jarvis’ subsidiary Prismo – in conjunction with the Transport Research Laboratory Ltd. (TRL) – has developed Rippleprint. This revolutionary new surfacing technology creates noise and vibration to alert the driver inside the vehicle, but without any increase in noise levels outside the car, a major issue with traditional traffic calming features. Already in use in many Local Authorities across the UK, Rippleprint improves road safety by targeting the offenders and helping rid the local environment of unnecessary noise pollution.

A new approach to traffic calming
Traditional speed calming measures – from speed humps and chicanes to rumble strips – have their disadvantages, especially in urban areas.

In 1999, scientists at the TRL began working on a new solution: a profiled road surface which creates high noise levels inside the car and encourages drivers to slow down, but without any increase in noise levels outside the vehicle.

In early computer modelling, the idea worked well. The next challenge for TRL was to put the theory to the test. TRL joined forces with Prismo to build test surfaces with different wavelengths and profiles, using their market-leading road surfacing technology.

Practical application
Prismo’s technical teams worked to iron out some important practical issues, developing a system to apply the surfacing – now known as Rippleprint – without distorting the vital wave profile. They designed an on-off ramp to give drivers a smooth run-up to the surface and included a narrow, smooth strip at the road edge to ensure that cyclists’ comfort would not be compromised.

Tests at a number of public road trial sites have proved extremely successful, with no noticeable increase in road noise for residents, but a measurable reduction in personal injury accidents. For example, on the first test site at Fleet in Hampshire, personal injury accidents dropped from 13 in the preceding 3 years to just 2 in 14 months. The resulting saving on the cost of accidents on that stretch of road alone has been estimated at over £130,000 a year.

As Highways magazine reported in August 2002: “Rippleprint,… has been a remarkable story of successful collaboration between government, scientists, commercial interests and customer, to the benefit of the public at large”.

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• Prismo website
  
  
Factfile

• Developed in close collaboration with Transport Research Laboratory Ltd
• Quieter than any alternative traffic calming surfaces
• Helps meet government targets on accident reduction
• Installing Rippleprint reduced personal injury accidents by 60 to 70% on all sites tested with an accident record