# Application of Machine Learning to Include Honking Effect in Vehicular Traffic Noise Prediction
## 2 Materials and Methods  
### Dataset and Sites Description  
The data used in this paper has been collected on the busy urban roads of the Patiala city in India (Figure 1). Besides the equivalent continuous sound pressure level (\(L_{\text{eq}}\)), the data collection included the parameters traffic volume (Q), percentage of heavy vehicles (P) and total honking occurrences (H) that have been used to calibrate and test the machine learning models. These parameters have been collected manually using videography at five different identified sites, highlighted in Figure 1, on the basis of congestion, presence of honking noise and proximity to resident population. For each video, the numbers of light and heavy vehicles have been annotated, as well as the number of honks in each 15 min measurement. In order to include the effect of horn noise in the prediction model, the number of honking events per 15 min was recorded. The values of the equivalent sound pressure level (\(L_{eq}\) in dBA) have been experimentally measured using a sound level meter (SLM, B&K make, 2250). The sound level meter used was a class 1 integrating type, which meets with the IEC specifications (IEC 61672-1: 2002, International Electrotechnical Commission, 2002) [33]. The SLM was mounted on a tripod (in order to avoid the human body impedance effects), at a height of 1.2 m above the ground level [34] and at a distance of 1 m from the edge of the road where the traffic noise measurements were taken. A brief description of the sites is given below. Site 1: This site is located near the Hanumaan Temple, on the road connecting the Mini-secretariat and Gurudwara (a Sikh temple) Dukhniwaran Sahib (Figure 2a). The road has one-way traffic with a median/divider in the middle. The traffic is free-flowing with all types of vehicles lying on the road. There are no traffic lights or a roundabout near the measurement point. The noise generation is mainly due to the vehicle noise and tyre-road interaction noise. There is a thick belt of trees on one side of the road, which leads to noise attenuation by absorption due to the thick foliage. Site 2: The site consists of a two-way road near the Modi Temple, connecting the Passy road to the State College road (Figure 2b). There is free-flowing traffic, with mainly cars and two-wheelers, and no traffic congestion. On one side, there is open land of the Modi temple ground with some sparse trees and boundary wall. Thus, there is some noise attenuation happening due to air-absorption. On the other side there are residential houses, mostly double storied, that may provide some noise attenuation. Site 3: It consists of the road connecting the Gurudwara Dukhniwaran Sahib with the Passy road (Figure 2c). The speed of the vehicles is low here because of a narrow section through which the vehicles enter and also because of some fruit stalls and shops nearby. Due to the low speed and some congestion, more honking events have been observed. Site 4: It is located on the road in front of the main entrance of Gurudwara Dukhniwaran Sahib (Figure 2c). The road is a one-way road with a median/divider in the middle. Figure 1: Area under study and sites of measurement (courtesy of Google Maps®). The traffic volume is very high as the vehicles arrive from different sections of the city and converge here to pass through this bottle-neck section and then go to Mini-secretariat road or the Sirhind road. There is a large number of heavy vehicles passing through this section as the vehicles coming from bus stand or other areas move out of the city using this road, to reach the Sirhind road and then subsequently to the national highway. On one side there is the Gurudwara Sahib main premises and the outer boundary wall, and on the other side, there are shops. High traffic noise levels are observed here due to the large traffic volume as well as honking. Site 5: The site is situated near the Patiala Bus stand (Figure 2d). A lot of cars, two wheelers and three wheelers pass through this section.