M42 road noise: how it affects nearby properties
The M42 arcs around the eastern and southern side of Birmingham, linking the M5, M6 and M40 and carrying a heavy mix of commuter and freight traffic near Birmingham Airport and the NEC. For properties near the M42, the combination of sustained daytime flows and overnight freight movement means night-time levels often deserve as much attention as the daytime figure.
Traffic on the M42: what the 2025 DfT counts show
The M42 is really two roads in one dataset. Its 36 count points include 14 above a hundred thousand vehicles a day and 25 above fifty thousand, yet the lowest quarter sits below 45,600 and the lowest tenth below 16,000, with a minimum of 10,545. The median is about 76,600 a day, but the upper quarter begins at 117,600, the busiest tenth start at 128,700 and the peak reading is 138,454. For a buyer the median is the least useful number here. Whether the nearest count point is a 16,000 one or a 130,000 one decides almost everything, and nothing on the road falls under ten thousand.
Follow the M42 from its south-western end at Catshill, near the M5, and the first third is the heavy part: 10 count points with a median of 115,000 vehicles a day and a top reading of 136,724. The long middle third has 23 points and a lower median of 73,700, yet it holds the road's maximum of 138,454. The final third, only 3 points, eases to a median of 66,100 as the road nears junction 11 and carries on as the A42. Along the way, junctions 4 to 7 remain a dynamic hard shoulder section, and the junction 6 scheme added junction 5a with a 2.4 km A4545 link that opened to traffic on 18 December 2024.
At the median M42 count point, 11.4% of traffic is lorries. The range runs from 6.4% at the lightest point to 16.5% at the heaviest, and only the heaviest tenth are above 15.1%. That matters most after dark, because the freight element means overnight movements can add to the picture as much as the daytime flow does. AcoustaPLOT takes the share recorded at a count point on this road, so a freight-heavy stretch is not averaged away into a single figure for the whole motorway.
| Quarter of points carry under | 45,600 vehicles/day |
|---|---|
| Median point | 76,600 vehicles/day |
| Three-quarters carry under | 117,600 vehicles/day |
| Busiest tenth carry over | 128,700 vehicles/day |
| Busiest single point | 138,454 vehicles/day |
The M42 on the ground
- The M42 is about 40 miles long, from Catshill near the M5 to junction 11, where it continues as the A42 towards East Midlands Airport. en.wikipedia.org
- It opened in sections from November 1976, with the link to the M5 completing the motorway on 19 March 1987. en.wikipedia.org
- A 2006 pilot over roughly 11 miles between junctions 3A and 7 let traffic use the hard shoulder at peak times, with a 50mph limit. expressandstar.com
- Junctions 4 to 7 remain a dynamic hard shoulder section; plans to convert it to permanent all lane running have been cancelled. nationalhighways.co.uk
- The 282 million pound junction 6 scheme added a new junction 5a and a 2.4km A4545 link, opened to traffic on 18 December 2024. nationalhighways.co.uk
- For the junction 5a to 6 link, planners proposed low-noise surfacing and sinking most of the new road below ground level to cut roadside noise. nsip-documents.planninginspectorate.gov.uk
- The section between junctions 7A and 9 was rebuilt during M6 Toll works and forms the link to the toll road's southern end. en.wikipedia.org
How loud is the M42, and how fast does it fall away?
The M42 table is easiest to read as pairs, typical flow of about 76,600 vehicles a day first and busiest, about 128,700, second. At 20 m from the nearest carriageway on open ground the Lden reads 80 and 82 dB. At 50 m it is 77 and 79, at 100 m 74 and 76, and at 200 m 72 and 74. Two decibels separate each pair. Everything assumes level, empty ground with no cuttings, buildings or fences, which is unusual beside a motorway, so a real address will land above or below these. Even the quietest entry, 72 dB at 200 m, exceeds the WHO guideline of 53 dB Lden by a wide margin.
| Flow | 20 m | 50 m | 100 m | 200 m |
|---|---|---|---|---|
| Typical section (76,600 vehicles/day) | 80 | 77 | 74 | 72 |
| Busiest tenth of sections (128,700+ vehicles/day) | 82 | 79 | 76 | 74 |
Areas near the M42
Passing through: Worcestershire · West Midlands · Warwickshire · Staffordshire.
Housing around Solihull, Water Orton and the Coleshill area sits close to the route and its major interchanges, where merging traffic and gradients can add to the noise. The terrain here is relatively flat, so distance and any purpose-built barrier do much of the screening work — exactly the kind of case AcoustaPlot's Barrier Design report is built to quantify for a specific garden.
Recent on the M42
Between junctions 3a and 7, in Warwickshire and Solihull, the M42 was the UK's pioneering “Active Traffic Management” scheme — the country's first hard-shoulder-running smart motorway with mandatory variable speed limits, opened in 2006 and later extended north to junction 9.
How AcoustaPLOT assesses M42 noise for your property
AcoustaPLOT starts an M42 assessment by finding one of the road's 36 DfT count points that lies on the M42 and within 8 km along it. Readings here range from 10,545 to 138,454 vehicles a day, so which point is chosen counts. Its flow and lorry percentage are then combined with the actual distance, terrain, ground cover, buildings or barriers in the way, and other roads or rail. The surroundings are described as fairly flat, so distance and purpose-built barriers do most of the screening work. It reports the day-evening-night (Lden) and night-time (Lnight) levels at your facade, and reads Defra's mapped value for any railway noise where available.
Check my property near the M42 →
M42 noise: common questions
Is the hard shoulder running between junctions 4 and 7 still in place?
Junctions 4 to 7 remain a dynamic hard shoulder section, and plans to convert it to permanent all lane running have been cancelled. A 2006 pilot over roughly 11 miles between junctions 3A and 7 first let traffic use the hard shoulder at peak times under a 50mph limit. For noise, the measured flow matters more than lane arrangement, and the long middle third of the road has a median of 73,700 vehicles a day.
How was noise handled on the new link between junctions 5a and 6?
Planners proposed low-noise surfacing and sinking most of the new road below ground level to cut roadside noise. The 2.4 km A4545 link was part of the 282 million pound junction 6 scheme, which also added junction 5a, and it opened to traffic on 18 December 2024. The open-ground table on this page makes no allowance for either measure, so a home beside the link needs its own address assessment.
Is the north-eastern end, where the M42 becomes the A42, much quieter?
Quieter than the south-western third, but far from rural. The last third has only 3 count points, with a median of 66,100 vehicles a day and a highest reading of 67,744, against a median of 115,000 in the first third. Junction 11 is where the motorway continues as the A42 towards East Midlands Airport, and the section between junctions 7A and 9 was rebuilt during M6 Toll works.
How much does 100 m of distance from the M42 achieve on level ground?
On open flat ground a typical flow gives 80 dB at 20 m and 74 dB at 100 m, a drop of six decibels. At the busiest sections it falls from 82 to 76 dB over the same gap. Going on to 200 m takes off about two further decibels in both cases. Because the terrain here is relatively flat, a purpose-built barrier is the kind of case AcoustaPLOT's Barrier Design report is built to quantify for a specific garden.