Noise Assessment during Motor Race Events: New Approach and

Innovative Indicators

AURORA MASCOLO1, DOMENICO ROSSI1, ANTONIO PASCALE3, SIMONA MANCINI2,

MARGARIDA C. COELHO3, CLAUDIO GUARNACCIA1

Via Giovanni Paolo II, I-84084 Fisciano (SA),

ITALY

Abstract: - Motorsport races significantly affect, on a local scale, noise pollution even if they do not represent

the majority of its contribution, which is a prerogative of road transportation, railways, airports, and industries.

Nevertheless, such noise emissions surely affect the well-being of inhabitants in the surrounding area of the

circuit. In fact, during a motor race event, vehicles produce high noise emissions while on tests, qualifying, and

race sessions. Since noise indicators commonly used in national regulations are computed over fixed times, it is

challenging to properly assess the total noise emission and immission at the receivers during such events.

Moreover, in literature, only a few works can be found assessing this specific issue, and consequently, there’s

emission at a certain receiver of a motor race event by knowing the number and type of cars involved, without

using the duration of the race itself.

Key-Words: - Acoustics, Noise Control, Noise Emission, Motor Race Events, Modelling and Simulation

Received: December 9, 2022. Accepted: January 5, 2023. Published: January 31, 2023.

Among all the pollutants daily threatening human

health, noise is one of the most relevant. In urban

areas, the primary contribution to noise level comes

term (chronic hypertension) consequences, [2], [3],

[4], [5], [6], [7], [8], [9], [10], [11]. Several studies

can be found in the literature assessing and

modelling road traffic noise emissions and

propagation (see for instance [12], [13], [14], [15]).

On the other hand, sports cars' noise emissions

(during motor race events) have peculiar aspects

that need to be deeper investigated. These events are

characterized by large sound pressure levels

produced by sports cars, which usually do not

emissions is not negligible, not only in terms of

spectators and workers but also citizens living

nearby, [16]. Since specific scientific papers are not

many in the literature, more and deeper

recorded noise levels reached a threshold that

suggested wearing appropriate protections. In this

case, common A-weighted continuous equivalent

levels (Leq,A) are used to assess the noise emitted

from the racing cars, applying it to the time of

measurement. Other subsequent works have focused

on noise emissions during a car race, [19], [20],

[21], [22], but still, no new and dedicated indicators

are presented. The lack of specific regulation for

noise emission reflects on the missing indications

typically with variable time length.

To fill this gap, in this contribution, the authors

report the new approach presented in, [23], to

deepen the characterization of noise emissions

during motor race events by introducing two new

acoustic indicators, namely LEL (Lap Equivalent

Level) and REL (Race Equivalent Level). These

indicators will allow predicting the total noise

emission at a certain receiver of a motor race event

by knowing the number and type of cars involved.

the particular nature of the events themselves. The

most used indicator in literature and many

regulations is the equivalent continuous A-weighted

sound pressure level – Leq,A. It is an energetic

parameter that provides a very useful description of

fluctuating (time-varying) sound levels. It is

expressed as in equation (1):

where T stands for the time interval of interest,

usually fixed by regulation or by measurement

duration, pA is the A-weighted sound pressure in

Pascal and p0 is the reference sound pressure equal

to 2 ∙ 10-5 Pa. The Leq,A gives a single value in dB(A)

that takes into account the total sound energy over

the entire time period of interest. Starting from this

where the time span of the emitted sound depends

on the whole race which, in turn, depends on how

many times the cars are turning the whole circuit.

continuous sound level immitted at a certain

receiver by a single vehicle in one lap of the track.

The mathematical formulation of LEL is reported in

equation (2):

where, tlap is the time, expressed in seconds, that a

vehicle needs to perform a single lap of the track.

as the equivalent continuous sound level immitted at

a certain receiver during a race by all the vehicles

running on the track:

robustness. A more detailed description of the

applications is reported in [23].

civil applications since it must fulfill the

requirements of the sports federations' regulations.

In this case, it is made of 6 cm-thick circuit-draining

asphalt, which is highly porous and draining.

Figure 1 and Figure 2 show the geographical

position within the Campania region, as well as the

track layout, with the points selected for the

measurements (A, B, C). The technical details of the

of 94 dB at 1000 Hz. Sound pressure level – Lp was

measured every 100ms, while a Formula X category

vehicle was running on the circuit. The vehicle was

a single-seater car, equipped with a 1.6 L engine,

the track), as shown in Figure 2, using two Class 1

sound level meters (respectively Panasonic

Soundbook MK2 and FUSION). These two points

are placed at a turn situated about 15 and 30 m from

the roadway respectively. Figures 3 and 4 offer a

different point of view of the Sound Level Meters

positions in points A and B. It is also important to

track.

a lap time. The maximum absolute difference

between lap time estimations and lap time values

from telemetry is 0.4 seconds which is no bigger

respectively for point B and point C. Each row

refers to a category of the competition event.

possible boundary conditions, given two receivers

(as in the case reported in Table 3), it is expected to

have a higher noise emission at the receiver that is

nearer to the carriageway. However, in the

presented case, REL values are generally higher at

receiver C than at receiver B even though it was

positioned at 30 meters from the carriageway while

Table 3. REL measured in points B and C during

races and the time of each race.

Source-receiver distance is the easiest

contribution to be explained: the greater the distance

the lower the recorded emission levels. Hence, the

choice of the receiver position is crucial for a

correct evaluation of LEL and REL.

It also has to be taken into account that various

types of vehicles, having diverse kinds of engines,

mufflers, and insulation, correspond to different

noise emission levels. In the case analyzed in this

work, there are vehicles obtained from historic twin-

equivalent sound level calculated over a race time

interval, its value is dependent on speed as well. For

the same reason, since each race can be

characterized by a specific number of participating

vehicles, it must be considered for the REL

estimation.

Another crucial contribution is given by the

drivers’ behavior. For example, in the hypothesis

that a driver maintains a slightly lower speed (as in

the measuring point B of the studied circuit) by

recorded at receivers positioned on a straight part of

the track, will be particularly high: in fact, vehicles

pass at maximum (full) speed on rectilinear parts,

generating high sound levels. On the opposite,

vehicles’ speed could be particularly low along

chicanes and turns, and as a consequence of that,

LEL and REL values could be lower at these

receiver points.

focuses on the comparison between REL measured

in points B and C during different races showing

curve, i.e. the integral shown in equation (3)

calculated as a function of time, increasing the

upper limit during the event. It must be stressed that

running REL values are plotted at every tenth of a

second (always considering the start of the race as

the initial time for REL computations).

be related to the cars’ passing in front of the two

receivers. It is interesting to notice how REL value

tends to stabilize after about two laps by the race

pressure level, due to the repetition of the laps, leads

to a little influence of the overall trace on the running

REL estimation (see also literature, [22], [25]).