NOISE IMPACT ASSESSMENTS
for LEGAL PURPOSES
(Draft #6)
Peter S Bright, NZCS (Physics)

Introduction: Noise legislation often refers to offences created by “unreasonable” noise
levels. Nobody knows what “unreasonable” is until a matter goes to court and the
magistrate rules on it according to the evidence. By then it is too late for the noise-law
enforcement authorities to back-track if they didn't have enough of it.

These authorities, mightily fearful of adverse repercussions should their prosecutions
fail, characteristically deal with this fear by ignoring the complainant's legitimate
grievance. This can include wilfully refusing to investigate complaints by simply not
attending the premises allegedly generating the offence. They also construct
illegitimate hurdles so that complainants will hurt themselves so badly when they
stumble that they never complain again. This is the main object of councils, for
example, in demanding that the victim compiles diaries over specified periods, even
years, thereby prolonging the victim's distress such that he eventually quits
complaining or moves out of the area. The whole situation has become an unaddressed
shambles and human suffering is rife.

What enforcement agencies need from the start is a combination of measured noise
intensity levels derived from electronic instrumentation and legally acceptable
evaluations of the subjective Impact of the Noise on the victim.

Thus enforcement bodies gathering evidence can derive a preliminary Noise Impact
Assessment Index which, if above a certain legislated figure, will justify prosecuting the
offender. The magnitude of the NIAI will be the principal decisionmaker.

Proposed: The following basic equation in general form is proposed as a combination of
noise measurement and the susceptibility of the human psyche to it. Noise level
measurements are secured electronically and then standardised functions modify their
mean value according to comprehensive professional research findings on the
psychological effects of particular noises on humans.


NIAI = V/T = Average Noise Volume per second (normallised)

or NIAI = k.abcd.log {integral(0 to N) i(n) dt}


where V = the total Volume of noise produced over the monitoring period and T is the
Total Monitoring Period in seconds; and where

k is a normallising constant that sets the NIAI to 1 under standard quiet conditions; and
where

N is the Total number of discrete Noise emissions; and where

n is the unique number of each discrete emission; and where

a, b,c and d are functions (or constants) determined by the various psychological
assessments of the effects of the Impact of Noise upon the human psyche.
The functions a,b,c,d: There can be any number of coefficients and any, or all, may be
linear or in the form of mathematical functions.

“a” may be a constant that relates particular noise types to a reference noise. For
example it may be that barking, because of its discordancy, is found to have a more
severe unnerving effect on humans than the noise of a passing helicopter. “a” would
therefore be an Irritation constant.

“b” may be a function that deems night noises worse than day noises because of their
generally disruptive effect on sleep patterns. This function might be a sine squared
function peaking at 1am for example.

“c” may be a function that deems certain sections of the public more susceptible to
noise that others. Thus a recipient of neighbourhood noise who is sick at home would
qualify for a sickness rating, and a shift worker needing sleep at odd hours would qualify
for a rating that takes his particular rights into account.

“d” may be a function which takes into account the higher noise susceptibility of certain
age groups, for example the very young and the aged.

“a” and “b” and “c” and “d” may be any function that is mathematically derived as a
“best fit” desription of the general psychologically adverse effects of the particular
noise being evaluated.

The enforcement authorities will have no grounds to claim that the mathematics are too
compex because the weightings have already been decided for them with all of them
openly listed after having been passed by Parliament. All these enforcement authorities
need concern themselves with is the final NIAI – a single figure. These authorities may
still prosecute it the calculated NIAI is below 100, and they may still lose a case if they
prosecute when it is above 100, but the elements of guesswork and emotive or ignorant
bias, laziness, fiscal convenience and personal stupidity will have been much reduced.

This method allows a noise victim to derive his own Noise Index figure from the start.
He can then decide what to do without any authority being involved. Faking the figures
might be tempting for some but it will all come out in the wash when the magistrate,
should he see fit, amends them – with penalties for wilful fictions.

The potential for error still remains while any person not exposed to the noise (eg
magistrates) endeavours to fairly evaluate the adverse effects of it
upon the one who is.

Mathematicians and others are invited to criticise this paper and amend or shoot down
any mathematical process presented in this preliminary draft.


Peter Bright
Glenorchy
Tasmania
Australia