Introduction

Noise Definition

Environmental noise has been defined as “unwanted or harmful outdoor sound created by human activities, including noise emitted by means of transport, road traffic, rail traffic, air traffic, and from sites of industrial activity.” (European Union, June 2002)

Noise and Health

Noise may negatively impact an individual’s health, affecting quality of life through sleep disturbance, cardiovascular and metabolic issues, and cognitive impairment in children (European Agency, June 2025)

Noise can also have economic impacts by potentially affecting tourism, learning, studying, and workplace productivity. According to the World Health Organisation (WHO), noise is one of the top environmental risks to health (World Health Organisation, 2018).

Transport noise is the biggest source of environmental noise in Scotland, with around 1.4 million people exposed to potentially unhealthy noise levels.

A variety of health problems can be associated with noise. For example, heart disease derived from exposure to daytime traffic noise costs approximately £1.2 Billion per annum (DEFRA, 2008), and sleep disturbance is one of the most common consequences of noise pollution. Noise is also an equity issue, with evidence showing low-income communities worldwide are most likely to be exposed to unacceptable levels of noise (World Health Organisation, October 2023). In addition, people affected by poverty live in disproportionately large numbers on busy main roads and often do not have the choice of moving away.

The European Directive on Environmental Noise

The European Parliament and Council Directive for Assessment and Management of Environmental Noise 2002/49/EC, more commonly referred to as the Environmental Noise Directive (END), was published in July 2002 and adopted in 2004. END requires Member States to bring about measures “to define a common approach intended to avoid, prevent or reduce on a prioritised basis the harmful effects, including annoyance, due to exposure to environmental noise.” END objectives are as follows.

• To determine the noise exposure of the population through noise mapping.
• To make information available on environmental noise to the public
• To establish Action Plans, based on the mapping results, to reduce noise levels where necessary, and to preserve environmental noise quality where it is good. END does not set limit values, nor does it prescribe Action Plan measures (these remain at the discretion of the competent authority).

Legal Context in Scotland

In October 2006 the END was transposed into The Environmental Noise (Scotland) Regulations 2006, and these were further amended by The Environmental Noise (Scotland) Amendment Regulations 2018 to allow adoption of the new Common Noise Assessment Methods in Europe (CNOSSOS-EU) methodology.

The END legislation requires the strategic noise mapping, and related action plan process to be completed every 5-years on a rolling cycle. Since 2006 there have been four cycles, commonly known as rounds, of the END legislation, including the current round underway. Each round required a separate action plan for Major Roads and Railways, Agglomerations, and Major Airports. To increase the areas modelled for each round, the legislation included more intense movement limits, and area definitions. Major roads and Major railways are defined by vehicles passages per year. Major roads are mainly trunk roads however they include some local roads. The detailed Action Plan scope requirements for each round are shown in Table 1 below.

Table 1 - Action Plan Scope Requirements for END Rounds

Action Plan Type	Round 1	Round 2 and Round 3	Round 4
Major roads	> 6,000,000 Vehicle passages per year	> 3,000,000 Vehicle passages per year	As Rounds 2 and 3 (SG mapped all roads)
Major Railways	> 60,000 Train passages per year	> 30,000 Train passages per year	As Rounds 2 and 3 (SG mapped all railways)
Agglomerations	>250,000 population and 500 people per km2	>100,000 population and 500 people per km2	>100,000 population and 500 people per km2
Airports	> 50,000 air traffic movements per year	> 50,000 air traffic movements per year	> 50,000 air traffic movements per year

The Scottish Noise Action Plans describe how the Scottish Government has worked with stakeholders in identifying options for noise management and provides detail on how those actions will be delivered. The history of the TNAP is detailed in Table 2 below.

Table 2 - History of TNAPs

Round	Mapping Complete	Plan Published	Delivery Period	Action Plan
1	2007	2008	2008 to 2012	Transport Noise Action Plan (TNAP) 2008 to 2012
2	2012	31 July 2014	2013 to 2018	Transport Noise action Plan (TNAP) 2013 to 2018
3	2017	5 December 2018	2019 to 2023	Transport Noise action Plan (TNAP) 2019 to 2023

Round 4 of the noise mapping was due to be completed in 2022 and was required to describe the noise situation in 2021, with the related action plans due for publication in 2023. Delays in developing the noise maps, with a resultant impact on the development of the TNAP, occurred due to a number of factors, including significant changes in the calculation methods resulting in a more complex procurement process for noise mapping. However, work on transport noise management has continued during 2024 and 2025 and the modelling for round 4 will enable future noise maps to be created more efficiently, and has the potential to deliver future benefits in resource and costs savings.

Scope of the TNAP

The Round 4 mapping is now complete, and this Draft TNAP 2024 to 2028 is one of the set of five Scottish Noise Action Plans covering the areas described in Table 3 below.

Table 3 - Scottish Noise Action Plan Details

Noise Action Plan	Areas
Transport	All major roads, all trunk roads, all rail routes, and transport policy
Agglomerations	All urban areas with population greater than 100,000, and with population density greater than 500 people per km2 (Aberdeen, Dundee, Edinburgh, Falkirk, and Glasgow)
Aberdeen Airport	Aberdeen Airport.
Edinburgh Airport	Edinburgh Airport.
Glasgow Airport	Glasgow Airport.

Strategic Noise Mapping and Action Planning

Strategic noise maps for the Environmental Noise Directive (END) round 4 (for a 2021 base year) have been produced on behalf of the Scottish Government by Noise Consultants Limited (NCL).

The development of the model, its calculation, and analysis was undertaken using a Noise Modelling System (NMS) to deliver calculations of the noise level on a 10 metre grid, at a height of 4 metre above local ground level, for a range of sources and noise types, as required by the Regulations. The outputs from the model can be found on the Scotland's Noise website, where noise maps have been produced to show a geographical representation of noise levels across the entirety of Scotland for 2021, showing areas where people are exposed to high levels of environmental noise.

The noise model takes account of the requirements of the new modelling methodology introduced into law since the previous round of mapping. It uses advances in data and technology to calculate noise exposure levels with a higher level of accuracy and coverage than ever before based on information such as traffic flow, road type, and road surface data. No actual noise measurements were taken in the production of the strategic maps, as the regulations require mapping to be conducted by means of modelling according to a specific method. This is because sound levels can vary significantly based on factors including weather conditions or the time of day or year, introducing a level of uncertainty into the result. This is averaged out as part of the modelling process.

As a result, mapping data - although useful in helping identify priority areas for investigation - does not necessarily represent an exact picture of the current situation on the ground at any given locality on any given day.

For END round 4 the Scottish Government went beyond the minimum requirements in the Regulations and chose to include all road and rail sources major and non-major, as defined in Table 1 earlier.

The total lengths of major road and rail noise source are shown in Table 4 below.

Table 4 - Round 4 total sources mapped

Source Type (as defined in Table 1)	Length
Major Road	2,932 km
Rail	1,357 km

Details of the noise bands used in the strategic noise mapping, and the number of people exposed to the noise levels within these bands, are shown in Table 5 and Table 6 below respectively. The bands, relate to yearly average noise levels, and were chosen to reflect thresholds of increasing public health concern and to align with EU environmental standards for noise exposure.

Table 5 - Noise Bands Decibel (dB) used in mapping

Background	55-59	60-64	65-69	70-74	≥75
Annoyance	Minimal	Noticeable	High	Severe	Extreme
Typical traffic conditions	Suburban arterial road, moderate flow	Urban route, acceleration	Single carriageway trunk road,	Motorway or Bypass,	Motorway or bypass with significant freight

The metrics used to measure noise within the noise bands include Lden, and L night. These were chosen to reflect cumulative human exposure to environmental noise, and its health impacts, especially annoyance and sleep impacts, across different times of day. The day–evening–night noise level, or Lden, is a 2002 European standard to express noise level over an entire day. It imposes a penalty on sound levels during evening and night. Lnight focusses solely on nighttime exposure, and directly ties to sleep disturbance and health risks.

Table 6 - People exposed in Noise Bands Decibel (dB)

Noise Type	Noise Source	55-59	60-64	65-69	70-74	≥ 75	Total
Lden	Major roads	119,400	73,800	54,400	18,300	2,700	268,600
Lden	Major railways	46,600	24,300	7,900	2,000	300	81,100
Lden	Total	166,000	98,100	62,300	20,300	3,000	349,700
Lnight	Major roads	91,400	60,900	31,100	5,600	600	189,600
Lnight	Major railways	30,800	11,500	2,600	400	0	45,300
Lnight	Total	122,200	72,400	33,700	6,000	600	234,900

A list of the number of people exposed to noise levels within the noise bands for each round of END for road and rail are shown in Table 7 and Table 8 below respectively. These figures are cumulative, and relate to the END requirements noted in Table 1.

Table 7 - Population exposure from major roads in Rounds 1 to 3

END Round	Lden (dB) > = 55	Lden (dB) > = 65	Lden (dB) > = 75	Lnight (dB) > = 50	Lnight (dB) > = 60	Lnight (dB) > = 70
1	191,000	44,600	1,600	115,900	20,200	100
2	201,200	60,300	600	153,200	15,600	0
3	260,700	68,400	300	182,200	16,800	0

Table 8 - Population exposure from major rail in Rounds 1 to 3

END Round	Lden (dB) > = 55	Lden (dB) > = 65	Lden (dB) > = 75	Lnight (dB) > = 50	Lnight (dB) > = 60	Lnight (dB) > = 70
1	20,500	5,700	100	14,300	3,300	0
2	37,700	13,500	2,800	32,100	12,500	1,200
3	39,200	9,300	300	29,900	5,200	200

A list of the number of people exposed to noise levels within the noise bands for round 4 of END for road and rail are shown in Table 9 and Table 10 below respectively.

Table 9 - Population exposure from major roads in Round 4

END Round	Lden (dB) > = 55	Lden (dB) > = 65	Lden (dB) > = 75	Lnight (dB) > = 50	Lnight (dB) > = 60	Lnight (dB) > = 70
4	268,600	75,400	2,700	189,600	37,300	600

Table 10 - Population exposure from major rail in Round 4

END Round	Lden (dB) > = 55	Lden (dB) > = 65	Lden (dB) > = 75	Lnight (dB) > = 50	Lnight (dB) > = 60	Lnight (dB) > = 70
4	81,100	10,200	2,300	45,300	3,000	0