# Periodical Vehicle Inspections with Smart Technology
## 4 Discussion  
The novelty of the approach is in using the ELM327 device for OBD scans at such a large scale successfully. The results in Table 5 show that a large number of malfunctions, 10,183, were read from cars' OBDs at PTI stations in 2020 in Slovakia. Most of these cases were emission related and only 63 were classified as major defects at technical inspection. Nevertheless, it did detect the defects and the cars had to be repaired and inspected again within the 60-day period. By incorporating OBD readings into the PTI process through a mobile app, Slovakia has become the third country in the EU to do so and is in compliance \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \begin{tabular}{c} **Vehicle** \\ **Class** \\ \end{tabular} & \begin{tabular}{c} **Number of** \\ **Tests** \\ \end{tabular} & \begin{tabular}{c} **Number of** \\ **Defects** \\ \end{tabular} & \begin{tabular}{c} **Number of** \\ **Defects** \\ \end{tabular} & \
\begin{tabular}{c} **\%** \\ **\%** \\ \end{tabular} &
\begin{tabular}{c} **\%** \\ **\%** \\ \end{tabular} \\ \hline \multicolumn{5}{c}{**Major**} & **Dangerous** & **All** & **Dangerous** \\ \hline M1 & 78,343 & 29 & 4 & 0.04 & 0.01 \\ \hline M1G & 19,329 & 6 & 1 & 0.04 & 0.01 \\ \hline N1 & 8070 & 19 & 3 & 0.27 & 0.04 \\ \hline N1G & 5772 & 1 & 0 & 0.02 & 0.00 \\ \hline N2 & 1215 & 46 & 10 & 4.61 & 0.82 \\ \hline N2G & 331 & 9 & 0 & 2.72 & 0.00 \\ \hline N3 & 470 & 19 & 2 & 4.47 & 0.43 \\ \hline N3G & 151 & 6 & 0 & 3.97 & 0.00 \\ \hline O4 & 17 & 1 & 0 & 5.88 & 0.00 \\ \hline PS & 101 & 1 & 0 & 0.99 & 0.00 \\ \hline R3a & 691 & 1 & 0 & 0.14 & 0.00 \\ \hline R3b & 5 & 0 & 0 & 0.00 & 0.00 \\ \hline T1 & 915 & 8 & 6 & 1.53 & 0.66 \\ \hline T1a & 18,181 & 37 & 9 & 0.25 & 0.05 \\ \hline T1b & 158 & 3 & 1 & 2.53 & 0.63 \\ \hline T2 & 67 & 3 & 0 & 4.48 & 0.00 \\ \hline T2a & 749 & 1 & 0 & 0.13 & 0.00 \\ \hline T4a & 8 & 1 & 0 & 12.50 & 0.00 \\ \hline T5 & 61 & 4 & 0 & 6.56 & 0.00 \\ \hline Sum & 135,913 & 195 & 36 & 0.17 & 0.03 \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Summary of brake drive test performed by mobile app in 2021 in the Slovak Republic. Figure 12: Driving brake tests performed by mobile app in 2021 in the Slovak Republic by vehicle categories. with EU legislation. In 2021, there were similar results to those of 2020 regarding OBD readings, with more than 21,000 DTCs detected, out of which 77 were related to safety. The number of brake driving tests performed by the presented app show the importance of designing this tool. The fact it became mandatory in 2021 will create a lot of supervision options for preventing fraud in brake assessment at PTI stations. The drive brake testing feature introduced an affordable, very easy way to test vehicle brakes and contributes significantly to road safety, particularly for older cars where major defects are more likely to occur. The ability to detect brake-related issues through OBD readings also helps to prevent brake failure-related accidents, which are known to increase with the age of the vehicle. An innovative aspect of the proposed method is also the utilization of a smartphone's IMU for measuring vehicle deceleration, which detected more than 200 defects in vehicle brake systems, more than 20% of which were on heavy duty vehicles. This technology, combined with regular calibration of the phone's accelerometers, provides a cost-effective solution for accurate drive brake testing and contributes to overall road safety. The app has already been expanded and new features, such as On-Board Fuel Consumption Meter (OBFCM) readings, have been field tested. The OBFCM reading functionality will be the next step in the app's development, contributing to fuel consumption and emission monitoring in the EU passenger cars. The technology is very affordable, making it suitable for countries where the cost of technical equipment is a barrier to implementing PTIs. In conclusion, this paper highlighted the significance of utilizing smartphone applications in the PTI process.