## 2 Methodology
### Data Analysis  
The data collected from the vehicle through the OBD-II device contained 130 data points (observations) for each day. Table 2 provides the quantitative statistics on the data points from the recorded parameters. Observations were obtained at 5 s intervals during the morning and evening trips for a period of 4 days. The engine's revolution per minute, vehicle equilibrium speed, AFR, and MAF were acquired for both trips. Figure 6 shows the vehicle speeds recorded during the morning trips. The maximum morning speed was  
Figure 5: Maximum traffic density was calculated at University Road Peshawar, KPK, Pakistan, 34.0020\({}^{\circ}\) N, 71.4851 E\({}^{\circ}\).  
72 km/h, and the minimum was 1 km/h. Figure 7 illustrates the evening trip's temporal changes in vehicle speeds with the minimum equilibrium observed speed of 2 km/h and the maximum of 69 km/h. The minimum equilibrium speed observed during morning and evening trips during the 4 days was 1.00 km/h, while the maximum was 72 km/h. Figure 8 demonstrates the temporal changes in MAF in a trip originating from Phase 2, Hayatabad, observed over 4 days. The MAF in the morning trip varied from 0.01 g/s to 25.65 g/s. Figure 9 demonstrates the temporal changes in MAF in a trip originating from UET Peshawar, observed over 4 days. The minimum mass airflow rate observed in the evening trip was 0.15 g/s, while the maximum was 43.52 g/s. The engine's rpm varied from 643 to 2113 rev/min. The intake air temperature varied from 16 to 36 \({}^{\circ}\)C. The air/fuel ratio of gasoline fuel was 1.  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Days** & **Parameter** & **Min** & **Max** & **Mean** & **Standard Deviation** & **Variance** \\ \hline \multirow{4}{*}{Day 1} & Engine RPM & 643.00 & 2113.00 & 1372.20 & 423.25 & 179,143.69 \\  & Intake air temp & 16.00 & 36.00 & 24.50 & 4.95 & 24.47 \\  & AFR & 1.00 & 1.00 & 1.00 & 1.00 & 1.00 \\  & MAF & 2.00 & 22.82 & 5.49 & 4.49 & 20.14 \\  & Equilibrium speed & 2.00 & 62.00 & 21.48 & 17.10 & 292.44 \\  & (velocity) & & & & & \\ \hline \multirow{4}{*}{Day 2} & Engine RPM & 641.00 & 2499.00 & 1391.30 & 455.38 & 207,373.68 \\  & Intake air temp & 18.00 & 33.00 & 24.16 & 3.84 & 14.78 \\  & AFR & 1.00 & 1.00 & 1.00 & 1.00 & 1.00 \\  & MAF & 0.11 & 25.65 & 5.91 & 6.01 & 36.15 \\  & Equilibrium speed & 2.00 & 72.00 & 24.14 & 17.93 & 321.49 \\  & (velocity) & & & & & \\ \hline \multirow{4}{*}{Day 3} & Engine RPM & 640.00 & 2434.00 & 1402.80 & 473.68 & 224,369.17 \\  & Intake air temp & 25.00 & 35.00 & 29.98 & 2.55 & 6.51 \\  & ARF & 1.00 & 1.00 & 1.00 & 1.00 & 1.00 \\  & MAF & 1.00 & 23.00 & 6.17 & 5.27 & 27.78 \\  & Equilibrium speed & 1.00 & 63.00 & 23.54 & 16.49 & 271.82 \\  & (velocity) & & & & & \\ \hline \multirow{4}{*}{Day 4} & Engine RPM & 640.00 & 2626.00 & 1346.46 & 448.86 & 201,472.88 \\  & Intake air temp & 21.00 & 32.00 & 24.51 & 2.43 & 5.89 \\ \cline{1-1}  & AFR & 1.00 & 1.00 & 1.00 & 1.00 & 1.00 \\ \cline{1-1}  & MAF & 0.01 & 43.52 & 7.32 & 8.66 & 74.98 \\ \cline{1-1}  & Equilibrium speed & 2.00 & 69.00 & 25.70 & 18.04 & 325.62 \\ \hline \hline \end{tabular}
\end{table}
Table 2: Characteristic of all the parameters during morning and evening.  
Figure 6: Variations of equilibrium speed (velocity) in the morning.  
The quantitative statistics of all parameters collected from the test vehicle using OBD II during the morning and evening are summarized in Table 2.  
Table 3 shows the quantitative statistics of CO\({}_{2}\) emissions, speed, and density f from day 1 to day 4 of data collection. The CO\({}_{2}\) emissions were calculated using Equation (10), the density was calculated using Equation (11), and the speed was obtained from Table 2.  
Figure 8: Variations of MAF in the morning.  
Figure 7: Variations of equilibrium speed (velocity) in the evening.