Decibel limits

[lowdrag]

On the news this morning I saw that the police are clamping down on bikes and a mention of a 70 db limit coming into force. I assume that this is purely for bikes and will not apply to cars as well. I for one would not have either of my classics passing that law.

[singlecoil]

70db seems a bit on the low side but in general I approve of noise limits and their enforcement, whatever the source.

[davejf]

I saw that too but assumed it would be a drive by limit maybe.
My classic mini is around 95db and has straight cut gears so that may increase the drive by but not static.
Not sure some new cars would pass that like Ferrari and Lamborghini etc.
Will be interesting to see more details of what they propose.
I’m not sure it’s been thought through properly.

[TooMany2cvs]

lowdrag said:

On the news this morning I saw that the police are clamping down on bikes and a mention of a 70 db limit coming into force.

Got a source for that? (UK or France?)

Can't see any retrospective noise limits being legally enforceable.

[55palfers]

70dB is an odd number?
The HSE Noise at Work regs allow 80dB before anything needs to be done.
http://www.hse.gov.uk/noise/regulations.htm

[lowdrag]

The source was BBC Breakfast today.. I searched but found nothing except that the current static limit for bikes is 80 db.

[Allan L]

For any limit (in dB or dBA) to make sense you need to define the measuring point and the revs and/or power - e.g. for events held under RAC MSA rules the vehicle is static and the measuring point is quite close to the exhaust outlet. Too technical for BBC Breakfast of course, but not for the enforcers

[Cooperman]

70db might well be a sensible limit so long as the measurement is taken at 10 metres from the exhaust outlet at 45 degrees to one side.

[FiF]

The devil will be in the details on this one, but in principle I am in favour. Fed up of idiot children running around on bikes with about 4bhp, at least 2bhp of which is produced in noise. Which is all coupled with furious and unnecessary blips and twists of the throttle.

[a8hex]

FiF said:

... Which is all coupled with furious and unnecessary blips and twists of the throttle.

And while they are at it they could force manufactures to issue firmware updates to modern cars to stop them rev'ing like a kiddy shouting LOOK AT ME when you start the bloody thing. It's the one thing that irritates me on my XKR and it's all because someone thought it was sensible to leave a five year old in charge of the marketing dept one day.
Lots of modern "performance" cars do it.
BTW, I don't think it's just latter day exotica that would have a problem with a 70db limit, lots of quicker version of cars make a real racket, often for no real noticeable effect in their acceleration.

[untakenname]

Noise is too dependant on driving style to set an arbitrary default limit imo.
Had a cheap stainless steel exhaust on my car which sounded nice at full chat but droned from 4k to 5k which was annoying on the motorway and also at night when trying to be discreet (and cold starts early morning popping away),
Ended up getting an expensive HKS Legamax which is less nosiy than stick till about 6k then all hell breaks lose from 8-10k, cost a lot but is money well spent, measures 97db when tested at 6.5k.

[GC8]

I can fart at well over 70dB!

[MDT]

The IVA test lists a max sound level as "Must have a measured sound level not exceeding 99dBA." 70dBA is very quiet.

[Ransoman]

FiF said:

The devil will be in the details on this one, but in principle I am in favour. Fed up of idiot children running around on bikes with about 4bhp, at least 2bhp of which is produced in noise. Which is all coupled with furious and unnecessary blips and twists of the throttle.

I think given that these are usually ridden by chavs with no licence, insurance, tax, number plate or helmet, the volume of the exhaust should be the least of your concerns, at least round several areas of Aberdeen.

[tapkaJohnD]

Can't find any news reports, but this Northamptonshire Police item cites 85dB for "standard" cars: http://www.northants.police.uk/simple/press-releas...

But this VCA page cites 74dB for current production cars, a limit in force since 1996! http://www.dft.gov.uk/vca/fcb/cars-and-noise.asp

This Essex Police procedure document cites 80db, with some louder exceptions: https://www.essex.police.uk/getmedia/5a4aaf2f-105f...

Strangely, even the last does not mention how far the sound meter should be from the exhaust. Sound beys the inverse sqaure law, roughly, so distance is critical. The MSA's regulations for competition cars are extremely specific, see the Blue Book, Section J, Para 5.17.1 and following. https://www.msauk.org/assets/000bb2018completelow-...

John

Edited by tapkaJohnD on Monday 3rd September 10:10

[ewand]

Those limits seem very low - as in, BiB could have anyone with a modestly loud sports car if they fancied it.

eg. The Lotus Evora 400 standard exhaust is already too loud for pretty much all track days, as it typically measures 108-111 dB in static and ~98bB in drive by tests. https://www.pistonheads.com/gassing/topic.asp?t=16...

[GC8]

A flushing toilet is well over 74dB.

[Travs]

If it curbs the seemingly hundreds of Harleys driving through town every weekend, all with, apparently, no bloody silencer at all then I'm all for it. (Removes boring old fart headgear and breathes)

[spaximus]

This has done the rounds before but the devil is in the detail and depends on who is doing the testing. It has been a perceived problem with bikes for years, people taking off systems and replacing with modified ones.

The last time it was trialled it was pointed out to the police about SVA and IVA limits and they had no answer. Someone has decided to quote the figure for new cars and say that is the limit. It would not hold up in court if your car was fully legal.