Tyre/road noise measurements on ISO tracks using the modified CPX method Piotr Mioduszewski 1 Gdansk University of Technology ul. Narutowicza 11/12 80-233 Gdańsk, Poland Truls Berge 2 SINTEF Digital, Acoustics P.O.BOX 4760 Torgarden NO-7465 Trondheim, Norway

ABSTRACT

Tyre rolling noise test method specified in the UNECE Regulation 117 is directly used in the Tyre Labelling Directive. Noise level specified on EU Tyre Label of each new tyre available on the European market was determined based on vehicle coast-by noise measurements performed on the standard reference road surface proscribed in the ISO 10844:2014. Available data from investigations by the vehicle and tyre industry and results from the STEER project show that the effect of ISO test track is significant.

To estimate the noise variation on existing ISO test tracks, a small Round Robin Test was conducted on 3 of them, as a part of the joint Polish-Norwegian project ELANORE. The modified CPX method was used for this purpose. Measurements were performed for 9 selected tyres of summer, winter and all-season type, with label noise values ranging from 66 to 74 dB. Additionally, 2 standard reference tyres, P1 (SRTT) and H1 (Avon AV4), specified in the ISO 11819-3:2017 were tested.

The obtained differences in noise levels for the tested tyres were up to 3.7 dB depending on test track. The ranking of tyres regarding measured noise levels didn’t correspond at all to the noise values given on tyre labels.

1. INTRODUCTION

The European Union Regulation (EC) 1222/2009 [1] on tyre labelling came into effect on November 1 st , 2012. Initially, the labelling obligation only applied to passenger car and van tyres. The labels were introduced to help consumers make an informed purchase decision when they replace their tyres, providing clear and relevant information about the quality of the tyres regarding

1 pmiodusz@pg.edu.pl 2 truls.berge@sintef.no

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to three parameters: fuel efficiency, wet grip and external rolling noise. Since May 1 st , 2021 a new Regulation (EU) 2020/740 [2] is in force, replacing the old one. The obligation of labelling was extended to cover bus and truck tyres. The new regulation introduced also options to show if the tyres are suitable for use in severe snow conditions or in extreme climatic situations.

Tyre labels provide to the consumers, including buyers of replacement tyres, with information on three of the main performance properties through pictograms – see Figure 1.

Figure 1: The EU Tyre label valid from 1 May 2021 [2]

The global objective of the Tyre Labelling Regulation is to increase safety as well as to make road transport more efficient and less harmful to the environment by promoting economical and safe tyres with low noise level. Rolling resistance affects Environmental Protection (CO 2 emission reduction), coast-by rolling noise affects Health Protection , wet grip affects Safety (braking distance, handling). And although the tyre performance parameters presented on the label are not directly linked to a particular vehicle it is important that the consumer experiences this also when using the vehicle. Rolling resistance of tyres accounts for 20 % to 30 % of the fuel consumption of a vehicle [1] and always in conjunction with its power-train efficiency, road surface and, the most important, driver’s behaviour. Tyre label value for noise relates to the external noise of a vehicle and not directly to the noise inside the vehicle compartment. Wet grip label value directly affects the braking distance of the vehicle on wet road surface, and there is no clear correlation with the behaviour of the tyre on dry surface which is much more influenced by road surface type and condition. That is why it is so important that consumers trust in the labelling system.

Measuring methods of the three tyre parameters are specified in the UN ECE Regulation 117 [3]. The rolling resistance tyre label value is obtained when measured in a laboratory conditions on a drum equipped with a very smooth surface and it may not correspond to the behaviour of the tyre on normal trafficked roads. The tyre noise label value is measured on a smooth dense asphalt

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concrete surface specified in ISO 10844:2014 [4] which was first standardized in 1994 with the aim of giving a low contribution from tyre/road noise. It was used for type-approval of noise emitted by accelerating road vehicles (ISO 362-1 [5]) as the main focus at that time was on power-unit related sources.

Several investigations have shown a lack of representativeness of the given tyre label values and how the tyres behave on real roads [6, 7]. Tyre/road noise, the dominant noise source in a vehicle, is very much dependent on road surface and the very smooth texture of the ISO reference pavement is not fully representative to the conventional pavements used on roads in real conditions.

The following investigations – Round Robin Test of ISO tracks in Europe performed by VDA [8], Tyre Performance Study done by ACEA [9], a small RRT conducted by the tyre industry (ETRTO) and from the STEER project – revealed also that the reference road surface, even it is specified in ISO 10844:2014 [4], it shows spread in obtained noise results when testing the same tyres on different test tracks. To verify these findings the ELANORE project was founded with the main objective to improve the EU Tyre Labelling procedure for rolling resistance and noise.

2. THE ELANORE PROJECT

The main objective of the ELANORE project (Improvement of the E U tyre LA belling system for NO ise and rolling RE sistance) [10] is to improve the efficiency of the EU tyre label, concerning both rolling resistance and noise. This international project, founded within a joint agreement between Norway Grants and the National Centre for Research and Development (NCBIR) in Poland (POLNOR 2019 Call – Energy, transport and climate) is carried out by a consortium consisting of Gdansk University of Technology (GUT), SINTEF (Norway) and EKKOM (Poland).

Two work packages of this project deal with tyre/road noise. Their goals are to verify representativeness of the tyre/road noise test method specified in the UNECE Regulation 117 with a special attention to verification of representativeness of the standard reference road surface proscribed in the ISO 10844:2014 [4] (t his method is used directly in the Tyre Labelling Directive) and to improve the effectiveness of the EU Tyre labelling procedure for noise performance of passenger car tyres.

The verification was planned to be done by a small Round Robin Test on selected ISO test tracks using a vehicle and limited number of sets of passenger car tyres. Additionally, vehicle coast-by noise tests were planned to be conducted on selected conventional, most common dense and porous pavements in Poland and Norway. Additional noise measurements using a modified CPX method [11] were planned to be done at the same locations for the previously selected as well as for a few additional tyres to validate the tyre noise labels in real road conditions.

Finally, based on the obtained results from the RRT of the selected ISO test tracks together with the results from performed road and drum noise tests, an improved tyre labelling procedure will be proposed. It is expected, that the new procedure correlates much better with real road results than the present one.

This paper supplements itself with another paper presented at this conference entitled “Tyre/road noise measurements on ISO tracks according to the UN ECE Regulation 117” [12].

3. SMALL ROUND ROBIN TEST ON 3 ISO TEST TRACKS

A small Round Robin Test (RRT) to estimate the noise variation on existing ISO test tracks was planned and performed in the summer of 2021 on 3 selected ISO test tracks located in Northern Europe. The selected test tracks were constructed in 2015-2016. The reference surfaces of all the test tracks met the requirements of ISO 10844:2014 [4].

3.1. Test Program

The following measurements were planned to be conducted on each of the 3 test tracks (with one exception) during the Round Robin Test:

- controlled pass-by (CPB) measurements with a passenger car according to the UN ECE

Regulation 117 using 5 sets of C1 tyres including one set of SRTT tyres, - additional CPB measurements with an increased tyre inflation pressure and reduced tyre load

(compared to Reg.117 conditions), named CPB with modified test conditions, - CPX measurements using a modernized CPX trailer (property of GUT) with both Reg.117

and modified test conditions, - measurements of texture properties using a texture surface drone, - measurements of Sound Exposure Levels (SEL) during the CPB tests ( at 1 test track only) ,

with a microphone located at a height of 4,0 m and at a distance of 10 m from the centreline of the track for the purpase of later noise modelling using the Cnossos-EU prediction model.

Due to some adverse weather conditions on two of the test tracks only part of the planned program was achieved. The results of performed CPB measurements are not presented here, but can be found in the supplementary paper presented at this conference: “Tyre/road noise measurements on ISO tracks according to the UNECE Regulation 117” [3]. The results of Sound Exposure Level measurements are also not reported in this paper.

3.2. Test Tyres

For the purpose of noise tests within this small RRT, 9 different C1 tyre types (4 of them in sets of 4 tyres) covering the range of EU label noise values from 66 dB up to 74 dB with 1 dB step (1 to 3 noise bars) were selected and tested. Only one selected tyre from each tyre set was tested using the CPX method. The selected tyres consisted of 4 summer tyres, 3 winter and 2 all-season tyres. Additionally, the “Standard Reference Test Tyre” - SRTT (Uniroyal Tigerpaw) according to the ASTM F2493-14 was also included and tested. Furthermore, the standard reference tyre (Avon Supervan AV4), designated H1 according to the technical specification ISO/TS 11819-3:2017 [13] was also used in CPX tests.

The details of tyres selected and used for the purpose of CPX measurements are presented in Table 1. The Designation Code is the internal code used by GUT. The tyres of Yokohama, Michelin, Bridgestone, Evergreen and Uniroyal (SRTT) are the tyres which also were used in sets of 4 pcs. for the CPB measurements.

Table 1: Description of the selected and tested tyres for CPX measurements

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3.3. Test Vehicle

All the CPX measurements within this RRT were conducted using the CPX trailer Tiresonic Mk5 , property of GUT – see Fig. 2.

Figure 2: Test vehicle: the CPX test trailer, Tiresonic Mk5

Before the Round Robin Test the CPX test trailer has been completely modernized within the ELANORE project to accommodate test conditions specified in the EU Tyre Labelling procedure (much higher tyre load), to be prepared for the extensive measurement program (to speed-up numerous measurements) and to provide high level measurement precision at all times (new measuring sensors have been installed).

3.4. Test Conditions

Noise measurements were performed with tyre load and inflation pressure according to the values prescribed in the UNECE Regulation 117 [3] as well as with a modified test condition.

The tyre load and inflation pressure during tests were adjusted to the values calculated using the formulas given in Regulation 117. The values depend on the maximum load (load index) of the tyre. Uniform for all the tested tyres the load was 530 kg and the inflation pressure was set to 200 kPa in cold conditions.

At two of the selected ISO test tracks additional measurements were performed for different tyre load and inflation pressure conditions. In these modified conditions it was assumed that the tyre load and inflation pressure depend on a particular vehicle, in this case the Skoda Superb which was used for CPB measurements. Thus, the tyre load was 460 kg, which corresponds to an average load condition of this vehicle: car net weight of 1590 kg (including the driver weighting of 75 kg and 90 % of fuel), plus two passengers (each weighting 85 kg) and 80 kg of luggage. The regular inflation pressure according to the vehicle manufacturer for this Skoda Superb was 230 kPa.

The values of tyre load and inflation pressure used for both test conditions are summarized in Table 2.

Table 2: Tyre load and inflation test conditions for both CPX and CPB measurements

Test condition Tyre load

Inflation pressure

[kg]

[kPa]

Reg.117 530 200

Modified 460 230

Change – 13 % +15 %

The CPX measurements were performed with two test speeds of 50 and 80 km/h.

4. MEASUREMENT RESULTS

Due to adverse weather conditions (rain and wetness of test track), only a part of the planned measurements was achieved. Table 3 shows the completed test program on the three ISO test tracks for CPX measurements.

Table 3: Completed test program for CPX measurements

ISO track 1 ISO track 2 ISO track 3 Designation Manufacturer

Reg.117 Modified Reg.117 Modified Reg.117 Modified

T1252 Dębica X X X

T1254 Yokohama X X X X

T1257 Kenda X X X

T1259 Michelin X X X X

T1262 Vredestein X X X X

T1264 Bridgestone X X X X

T1267 Continental X X X X

T1268 Momo X X X

T1269 Evergreen X X X X

T1273 Uniroyal X X X X

T1182 Avon X X X

For the Reg.117 conditions, all tyres were tested at all 2 test tracks and 7 of 11 tyres were tested on the 3 rd one. For the modified conditions measurements were conducted on one test track only.

It has already been planned that supplementary measurements will be performed in July 2022 on one more ISO test track in Europe. Thus, in this paper only preliminary measurement results are presented. A final test report will be provided and complete results will be published and discussed in a reputable journal when the full test program on ISO test tracks has been achieved.

All measurement results presented in this paper were corrected for speed and temperature but were not corrected for tyre rubber hardness. The corrections applied were calculated according to the Annex of the ISO 11819-2:2017 [11] standard.

4.1. Noise Levels – Test Track Influence

The main results of measurements, A-weighted sound pressure levels of the average of front and rear microphone values, were presented in Table 4 and in Figures 3 and 4 (for the speed of 50 and 80 km/h correspondingly). Please observe that not all tyres were tested on ISO track 3 test track due to unpredicted unsatisfactory weather conditions (rainfalls).

Table 4: Noise levels of tested tyres on 3 ISO test tracks

Sound Pressure Level in dB(A)

50 km/h 80 km/h

Tyre

ISO track 1 ISO track 2 ISO track 3 Average Spread ISO track 1 ISO track 2 ISO track 3 Average Spread

T1252 85,4 86,3 85,9 0,9 92,5 93,9 93,2 1,4

T1254 84,6 84,7 84,7 84,6 0,2 90,8 91,7 91,2 91,2 0,9

T1257 85,3 86,4 85,8 1,0 91,4 92,4 91,9 1,0

T1259 84,4 85,6 85,2 85,1 1,2 91,4 92,9 92,5 92,3 1,5

T1262 84,6 84,9 86,6 85,4 2,1 91,3 92,1 94,0 92,5 2,7

T1264 85,4 86,9 85,8 86,0 1,5 91,6 92,9 91,6 92,0 1,4

T1267 85,7 86,7 86,2 86,2 0,9 93,4 93,4 92,5 93,1 0,8

T1268 87,3 88,4 87,8 1,1 95,3 95,6 95,4 0,3

T1269 85,1 85,4 84,1 84,9 1,3 92,6 93,2 91,8 92,5 1,3

T1273 86,9 89,1 88,1 88,1 2,2 92,2 95,9 94,7 94,3 3,7

T1182 89,0 90,5 89,7 1,5 95,5 96,9 96,2 1,4

max 89,0 90,5 88,1 89,7 2,2 95,5 96,9 94,7 96,2 3,7

min 84,4 84,7 84,1 84,6 0,2 90,8 91,7 91,2 91,2 0,3

avg 85,8 86,8 85,8 86,3 1,3 92,5 93,7 92,6 93,1 1,5

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Figure 3: Noise levels of tested tyres on 3 ISO test tracks for the speeds of 50 km/h

Figure 4: Noise levels of tested tyres on 3 ISO test tracks for the speeds of 80 km/h

The highest sound pressure levels were measured on ISO test track 2 for all the tested tyres with one exception. The average SPL values noted on ISO track 1 and 3 were comparable, although for the test speed of 50 km/h the noise levels obtained on ISO track 1 for all but one of the tyres were lower than on ISO track 3. For the speed of 80 km/h 4 tyres were louder and 3 tyres were quieter on ISO track 3 comparing to ISO track 1.

The obtained differences in noise levels between particular ISO test tracks for the test speed of 80 km/h were from 0,3 dB up to 3,7 dB (with the average of 1,5 dB) depending on the tyre. Excluding the 2 CPX reference tyres (SRTT and AVON) the maximum difference was 2,7 dB and the average was reduced to 1,3 dB. For the speed of 50 km/h the differences, somewhat smaller, were from 0,2 dB up to 2,2 dB with the average of 1,3 dB.

The spread between ISO tracks 1 and 2 only is from 0 to 3,7 dB for 80 km/h (1,2 dB the average) and from 0,2 to 2,2 dB for 50 km/h (average of 1,0 dB).

The calculated differences in noise levels between particular ISO tracks are presented in Table 5.

Table 5: Calculated differences in noise levels between particular ISO tracks

Sound Pressure Level difference in dB(A)

50 km/h 80 km/h

Tyre

ISO tracks

ISO tracks

ISO tracks

ISO tracks

ISO tracks

ISO tracks

2 minus 1

2 minus 3

3 minus 1

2 minus 1

2 minus 3

3 minus 1

T1252 0,9 1,4

T1254 0,2 0,0 0,1 0,9 0,5 0,4

T1257 1,0 1,0

T1259 1,2 0,3 0,9 1,5 0,3 1,2

T1262 0,3 -1,8 2,1 0,8 -1,9 2,7

T1264 1,5 1,1 0,4 1,3 1,4 -0,1

T1267 0,9 0,5 0,4 0,0 0,8 -0,8

T1268 1,1 0,3

T1269 0,3 1,3 -1,0 0,5 1,3 -0,8

T1273 2,2 1,0 1,2 3,7 1,2 2,5

T1182 1,5 1,4

max 2,2 1,3 2,1 3,7 1,4 2,7

min 0,2 -1,8 -1,0 0,0 -1,9 -0,8

avg 1,0 0,4 0,6 1,2 0,5 0,7

During the Round Robin Test the actual texture properties of each tested ISO test track were measured using the Surface Texture Drone of MüllerBBM. This drone measures the MPD value and the g-factor (averaged over the distance travelled with the drone and over each wheel track). Based on the measured texture values and using the known average absorption value for the frequencies between 315 Hz and 1600 Hz, a vehicle pass-by noise level at 50 km/h, L crs in dB(A) is estimated. The estimation of L crs is based on an equation developed from the Round Robin Test performed by VDA in 2016 [8], but later modified somewhat by MüllerBBM. The modelled L crs pass-by noise levels at 50 km/h are presented in Table 6.

Table 6: Modelled pass-by noise levels for the 3 ISO test tracks

Test track MPD [mm] Absorption α Modelled pass-by level

L crs at 50 km/h [dBA]

ISO track 1 0,59 0,05 62,4

ISO track 2 0,46 0,03 63,9

ISO track 3 0,47 0,04 63,7

Analysing the calculated pass-by noise levels, it can be observed that the measured surface properties of ISO track 2 make the test track the loudest one. Correspondingly, the properties of ISO track 1 make this track to be the quietest one. Those findings confirm to some extend the obtained results of the performed CPX measurements. The difference between ISO track 2 and 1 in modelled pass-by level at 50 km/h is 1.5 dB while the average difference for all the tested tyres using the modified CPX method for 50 km/h was 1,0 dB.

The MüllerBBM Surface Drone calculates also, on the same principles, the predicted CPX level at 50 km/h. The values for the tested ISO tracks 1, 2 and 3 are correspondingly: 89,9 dB (the highest of the 3 ISO tracks), 87,5 dB (the lowest) and 87,7 dB (very close to the lowest). One can easily notice that, surprisingly, they do not correspond with the modelled pass-by levels nor with the obtained CPX measurement results. The ranking of tested ISO tracks is totally different. The authors cannot explain the reason.

4.2. Tyre Load and Inflation Pressure Influence

The noise levels and their differences measured under different tyre load and inflation pressure conditions are shown in Table 7. All measurements were conducted on ISO track 2.

Table 7: Effect of tyre load and inflation pressure on measured noise levels

Sound Pressure Level in dB(A)

50 km/h 80 km/h

Tyre

Reg. 117 conditions

Modified conditions Difference Reg. 117 conditions

Modified conditions Difference

T1252 86,3 86,3 0,0 93,9 93,8 0,0

T1254 84,7 84,3 0,4 91,7 91,4 0,3

T1257 86,4 85,7 0,6 92,4 92,3 0,1

T1259 85,6 85,3 0,2 92,9 92,7 0,2

T1262 84,9 85,4 -0,5 92,1 93,1 -0,9

T1264 86,9 86,3 0,5 92,9 92,6 0,4

T1267 86,7 86,4 0,2 93,4 93,1 0,3

T1268 88,4 87,5 0,9 95,6 95,1 0,5

T1269 85,4 85,4 0,1 93,2 93,1 0,1

T1273 89,1 88,0 1,1 95,9 95,1 0,9

T1182 90,5 90,3 0,2 96,9 98,1 -1,2

max 90,5 90,3 1,1 96,9 98,1 0,9

min 84,7 84,3 -0,5 91,7 91,4 -1,2

avg 86,8 86,5 0,3 93,7 93,7 0,1

The average difference between the two test conditions is small, in the range of 0,1 - 0,3 dB. Depending on the tested tyre for the speed of 80 km/h the difference is from -1,2 up to 0,9 dB. For 50 km/h the range is similar: from -0,5 to 1,1 dB. The difference between the Reg.117 and the Modified conditions for 8 of 9 C1 tyres and for SRTT tyre is positive, while for one summer C1 tyre and for the Avon H1 reference tyre is negative. Please note that these conclusions are based on one single ISO track.

4.3. Tyre ranking

It was expected that the tyre ranking according to noise values given on tyre labels corresponds with the ranking according to measured sound pressure levels during CPX measurements on ISO test tracks as there is a clear correlation between CPB/SPB and CPX methods. The average value of SPLs at 80 km/h calculated for all test tracks were used for this comparison. The obtained results are presented in Table 8.

Table 8: Tyre noise ranking, compared to the noise label values as given by the manufacturer

ISO test track

Average of all test tracks Manufacturer Tread pattern Season

Tyre label

ISO track 1 ISO track 2 ISO track 3

Noise

Noise

SPL [dB(A)]

Position in ranking

SPL [dB(A)]

Position in ranking

SPL [dB(A)]

Position in ranking

SPL [dB(A)]

Position in ranking

bar

level

Dębica PRESTO UHP Summer 1 66 dB 92,5 6 93,9 8 93,2 8

Yokohama Advan Fleva V701 Summer 1 67 dB 90,8 1 91,7 1 91,2 1 91,2 1

Kenda KR501 Winter 1 68 dB 91,4 4 92,4 3 91,9 2

Michelin CrossClimate+ All season 1 69 dB 91,4 3 92,9 4 92,5 5 92,3 4

Vredestein Ultrac Satin Summer 2 70 dB 91,3 2 92,1 2 94,0 6 92,5 5

Bridgestone Blizzak LM005 Winter 2 71 dB 91,6 5 92,9 5 91,6 2 92,0 3

Continental AllSeasonContact All season 2 72 dB 93,4 8 93,4 7 92,5 4 93,1 7

Momo W-2 NORTH POLE Winter 3 73 dB 95,3 9 95,6 9 95,4 9

Evergreen EH23 Summer 3 74 dB 92,6 7 93,2 6 91,8 3 92,5 6

One can easily observe that the tyre ranking based on CPX noise measurements is totally different from the one based on noise values given on tyre labels. Neither the quietest nor the loudest tyre according to its label corresponds to the noise levels measured for these tyres with the modified CPX method. The positions in the middle of the stake are also different. Differences appear also between particular ISO test tracks. The cause of this inconsistency will be analyzed in detail after analyzing all the results obtained during the Round Robin Test and when tested in laboratory conditions.

5. CONCLUSIONS

The CPX tests on 3 test tracks with the reference ISO road surface were planned and performed as an additional measurement campaign to vehicle coast-by noise tests. A small Round Robin Test was conducted to estimate the noise variation on existing ISO test tracks. A modified CPX method was used. Tyre load and inflation pressure were fixed according to the values calculated for tyres using conditions specified in Regulation 117 for the purpose of tyre labelling.

Due to unfavorable weather conditions – rainfall and wetness of test tracks, only a part of the planned measurements was achieved. A follow-up is planned to be done in 2022 on one additional ISO test track. Nevertheless, based on the obtained results, the following conclusions can be formulated:

- The ISO test track 2 is characterized by the highest sound pressure levels measured for all the

tested tyres with one exception. - ISO test tracks 1 and 3 are comparable, although for the test speed of 50 km/h the noise levels

obtained on ISO track 1 for all but one tyres were lower than on track 3; for 80 km/h 4 tyres were louder and 3 tyres were quieter on ISO track 3 comparing to 1. - The obtained spread in noise levels between particular ISO test tracks for 80 km/h were from

0,3 dB up to 3,7 dB (with the average of 1,5 dB) depending on the tyre; for 50 km/h the spread was from 0,2 dB up to 2,2 dB with the average of 1,3 dB. - For the 9 C1 tyres only (SRTT and AVON excluded) the spread at 80 km/h was 2,7 dB and

the average value was reduced to 1,3 dB. - The average difference between the 2 test conditions used (according to Reg.117 and

Modified) is small and it is within a range of 0,1 - 0,3 dB. This difference for 8 of 9 C1 tyres and for SRTT tyre is positive, while for one summer C1 tyre and for the Avon H1 reference tyre is negative. - The ranking of tyres based on CPX noise measurements is totally different from the one based

on noise values given on tyre labels. The tyre ranking differs also for particular ISO test tracks.

This paper presents preliminary results of modified CPX measurements performed within a small Round Robin Test performed on 3 ISO test tracks. This RRT will be supplemented in 2022 by one additional ISO test track. Laboratory noise measurements of the same tyres on different road replica surfaces will be performed. CPB and CPX measurements on trafficked roads in Poland and Norway will be conducted. Finally within the ELANORE project, a proposal for improved procedure for noise labelling of C1 tyres will be presented.

6. ACKNOWLEDGEMENTS

The work of the ELANORE project has been made under the Programme "Applied Research under the Norwegian Financial Mechanisms of 2014-2019 between Norway Grants and NCBR, under the contract No . NOR/POLNOR/ELANORE/0001/2019-00.

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