Tyres, road surfaces and speed are taken into account in noise abatement plans – The Irish Times

Changes in regulations for tyres, road surfaces and speed limits are among the issues being considered by local authorities to reduce noise on city and state roads, but changes are not easy and every action has consequences.

Some people believe that growing sales of quieter electric cars will help solve the problem, but in reality, electric cars are only quieter when driven below 40 km/h – beyond which, for the most part, a car’s tires are responsible for the noise, not the engines.

The mix of tyres, speed and surfaces will feature prominently in the Environmental Protection Agency’s forthcoming noise action plans, but the solutions are “far from simple,” the agency admitted in an interview with The Irish Times.

Studies have shown that changes to tire treads can reduce noise but could affect road safety. While changes to the components used in urban pavements could reduce local noise levels, such changes could be dangerous on highways. Further research is required.

Every five years, “noise maps” showing decibel levels of roads, railways and airports are drawn up and submitted to the Environmental Protection Agency. This is followed by strategies for noise management, so-called noise action plans.

In the Dublin area, the Noise Action Plan 2018-2023 identifies “unwanted noise levels” of more than 55 decibels at night and more than 70 decibels during the day.

Noise is most severe on the roads, particularly on the M50 and nearby national roads, Dublin Airport and the city centre.

Noise levels in excess of 75 decibels – which can damage hearing over time – have been observed along much of the M50 from the M11 to the M1, and along many major access roads including the M11, the M7 (Red Cow), the M4 and M2.

Noise levels near the airport tended to be lower at 55 to 59 decibels. However, the EPA said the map this was based on predated the opening of the second runway. Fingal County Council is currently preparing a management plan for the airport.

High noise levels were also noted at Temple Bar, Westmoreland Street and the corner of Pearse Street and Tara Street, where levels were reported to be in excess of 75 decibels.

The noise level near the Luas lines was only 55 decibels. Higher levels of up to 69 decibels have been recorded in areas adjacent to major roads. A similar situation was found along the dart line.

The mitigation measures outlined by Dublin City Council mention “traffic avoidance plans combining walking, cycling and public transport” as well as “speed reduction plans which include partial access zones, smoothing traffic flow and reducing driving speeds” and “traffic flow shifting i.e. diverting traffic”. along non-residential buildings, less sensitive routes”.

Dún Laoghaire Rathdown Council has “driven two priority actions”. According to the council, its “numerous pedestrian and bicycle priority measures” result in “a general reduction in noise-causing car traffic”. The second action was the resurfacing of the N11 and N31 in conjunction with Transport Infrastructure Ireland.

A spokesman for the EPA said speed, tires and road surface would be among the most important considerations in upcoming noise action plans. However, he said reducing noise is “far from easy”. He said studies have shown that reducing tire treads can reduce noise, but there is a risk in terms of road safety. While there may be some leeway for changing road surface composition in urban environments, this could be potentially dangerous on highways with higher speed limits. He said more research is needed.

Transport Infrastructure Ireland said replacing some road surfaces, particularly in urban centres, would result in the newer surfaces having to be replaced more frequently, which would generate more CO2 emissions. The spokesman agreed that the noise issue is complex as lower speeds with consequent gear changes could lead to higher emissions.