EUKN - European Urban Knowledge Network - Effectiveness of traffic flow measures to reduce noise

Effectiveness of traffic flow measures to reduce noise

Introduction

Annoyance, lack of sleep and health complaints. Close to 80 million people in the European Union (EU) suffer from unacceptable noise levels. Road traffic is a major source of noise. The Danish Road Institute conducted a research on the effectiveness and benefits of traffic flow measures (chicanes, speedbumps, roundabouts) to reduce noise. Based on a thorough literature study, the author does not only assess these measures’ impact on noise levels, but also their effect on the annoyance of those living along the road.

Description

The report consists of three parts. The first part gives a theoretical background of the four parameters to take into account when evaluating the noise effect of traffic management measures. These are traffic volume, traffic composition, speed and driving pattern.

The second part discusses a wide range of traffic flow measures and their effect on driving pattern, noise emission and annoyance, which have been divided into six categories:

traffic calming – this includes humps, speed cushions, raised junctions, dummy humps, road narrowing and rumble devices
junctions – this includes (mini-)roundabouts and calming green waves (consecutive green traffic lights on a road to promote more even driving patterns)
dedicated lanes for specific types of traffic such as buses or trucks
signs – this includes static speed limit signs and interactive signs
automatic traffic control
other measures – this includes congestion charging, parking information systems, city logistics and night time bans
The third part presents the effects on noise that each traffic flow measure has with additional comments in a neatly arranged table.

Background information

According to the European Commission Green Paper on noise around close to 80 million people in the EU suffer from noise levels that scientists and health experts consider to be unacceptable. People become annoyed, sleep is disturbed and adverse health effects are to be feared. An additional 170 million citizens are living in so-called ‘grey areas’ where the noise levels are such to cause serious annoyance during the daytime. The majority of these people are subjected to noise from road traffic. The noise emission limits for new vehicles have been tightened over the years without this resulting in lower noise levels along the roads. The need for means to reduce road traffic noise is therefore great.

EU involvement

The report was written in the framework of the SILENCE project. The SILENCE project focuses on reducing surface transport noise in urban areas. It is partly financed by the 6th Framework Programme of the EU's Directorate-General for Research.

Conclusions

The research shows that the best results are likely to be achieved with measures that reduce traffic volumes, lower speed, and stimulate more even driving.

Narrow cushions and round-top humps are preferable from a noise perspective when reducing traffic flows. Correct distancing between such measures is important to avoid accelerations and decelerations. On major roads, however, reductions in traffic volumes are rarely feasible solutions to noise problems.
A number of traffic calming measures may be used to reduce speed on minor roads (humps, speedcushions, chicanes). However, on many large urban roads, most traditional traffic calming measures are inapplicable. On such roads, speed limits enforced through automatic traffic control or by police enforcement is the main measure available. Calming green waves may also be a possibility.
With regard to encouraging driving at a steady pace, several surveys have shown that roundabouts lead to less noise than intersections with or without signalisation. This is to a large extent because more vehicles can pass without having to come to a complete stand-still. Coordinated signalisation in the form of calming green waves may also be a measure to secure more even driving patterns.

The report, however, emphasises that the effect of a measure in a specific case will depend on the local conditions as to road layout, traffic composition and speed before and after the measure is implemented.

Contact info

Danish Road Institute
Lars Ellebjerg

Publication date

05/01/2007

Researcher

Lars Ellebjerg, Danish Road Institute

Links

SILENCE project website

Download 'Effectiveness and benefits of traffic flow measures on noise control' (PDF, Eng, 1.6 MB)

Document type

research

Themes

Urban Policy > Urban environment > Environmental sustainability

Keywords

Noise