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This study, entitled "A nalysis of Population Density, Economic Growth Rate, and the Number of Motorized Vehicles on Environmental Quality in Indonesia," aims to analyze: 1) the development of environmental quality in Indonesia; 2) the influence of population density, economic growth rate, and the number of motorized vehicles on environmental quality in Indonesia. This study employed a quantitative method, utilizing secondary data from 2019-2023, sourced from the Central Statistics Agency (BPS), the Ministry of Environment and Forestry (KLHK), and other sources. Panel data analysis tools, classical assumption tests, and hypothesis testing were used. Panel data regression results indicate that, partially, population density has a significant negative effect, economic growth rate has a negative and significant effect, while four-wheeled and two-wheeled motorized vehicles have a positive and significant effect on environmental quality in Indonesia. Meanwhile, collectively, population density, economic growth rate, and the number of motorized vehicles significantly influence environmental quality in Indonesia.

The braking system was a crucial component in ensuring the safety of motor vehicles on the road. Brake failures, such as brake fade or total malfunction, could result in fatal accidents. Therefore, an accurate and realistic testing method was necessary to measure the effectiveness of a vehicle’s braking system. This study aimed to develop a deceleration measuring device based on GPS, which could be used in road test methods. The device was designed using an ESP32 microcontroller combined with a BN-220 GPS module, RTC real-time clock sensor, 16x2 LCD, thermal printer, and microSD storage media. Testing was conducted on a Mitsubishi L300 vehicle at the Depok Beach runway in Yogyakarta, with initial speed variations ranging from 10 to 80 km/h. Calibration results showed that the device had an accuracy of 99.64% with an average error of 0.36%. Meanwhile, the test results recorded deceleration values ranging from 0.74 to 3.26 m/s², depending on the initial speed and braking conditions. Based on these findings, the developed device proved to be accurate and feasible as an alternative method for field testing of braking systems.

The rapid development of automotive technology requires students majoring in automotive vocational schools (SMK), particularly in the field of vehicle charging and starting systems, to understand the charging and starting systems. Charging and starting systems are two crucial components in ensuring vehicle operation. For students, having a strong knowledge of how these systems work, maintain, and diagnose them is key to facing the challenges of the automotive industry. Therefore, improving the quality of automotive education is essential so that students can master the basic concepts and techniques needed to carry out their duties as automotive technicians. This research focuses on developing a trainer that can help vocational school students better understand and master vehicle charging and starting systems. The trainer, developed at SMK NU Sunan Ampel Tumpang, records real-world conditions in vehicles using components such as batteries, alternators, regulator ICs, starter motors, and other supporting electrical systems. One innovative feature added is testing the effect of variations in pulley ratios on alternator output voltage and current. This feature provides students with the opportunity to conduct hands-on experiments, analyzing how variations in pulley ratios can affect the performance of a vehicle's charging system. It is hoped that with this trainer, students will not only gain theoretical knowledge but also practical experience that will enable them to perform diagnoses, understand the working principles of charging and starting systems, and analyze system efficiency based on rotational speed measurements. Thus, students' competency in the automotive field can be improved, and they will be better prepared to face the increasingly complex world of work. The successful development of this trainer can also serve as a valuable reference for educators and the automotive industry in designing applicable and contextual learning strategies.

The automotive sector continues to demonstrate significant progress in line with innovations in various supporting components of motor vehicles. Motorcycles, which initially served only as a practical means of transportation, have now evolved into a lifestyle element and a popular activity among many communities. Along with the increasing demand from consumers for performance and efficiency, the development of transmission technology, particularly the Continuously Variable Transmission (CVT) system, has become an important aspect that requires serious attention. One of the key components in the CVT system is the double clutch lining and the clutch housing, which play a vital role in transferring torque and power from the engine to the driving wheel. The performance of these components directly affects acceleration, efficiency, and engine durability. Therefore, research on the design and modification patterns of the double clutch lining and clutch housing is essential to determine an optimal configuration. This study applies an experimental method using a 110 cc motorcycle as the test object. Several modification patterns were applied to the double clutch lining and clutch housing to examine their influence on vehicle performance. The testing process was carried out using a dynotest, which enables precise measurement of torque and power across different engine speeds. The data obtained from these tests are expected to provide a clear overview of the effect of modification patterns on the transmission performance of motorcycles. The findings of this research are expected to contribute significantly to the development of more efficient and optimal designs for double clutch linings and clutch housings. Furthermore, this study may serve as a valuable reference for the automotive industry as well as motorcycle modification communities in enhancing vehicle performance while maintaining efficiency and component durability. In this regard, innovations in CVT components hold great potential to support the advancement of two-wheeled transportation technology in the future.

The rise in motor vehicle theft cases in various regions indicates the weakness of the security systems implemented by most users. Systems such as manual locks and alarms often fail to prevent crime, either because they are easily hacked conventionally or due to user negligence in their operation. In today's technological era, a system is needed that is not only secure, but also intelligent and practical. One promising solution is the implementation of a facial recognition-based security system. This study aims to design and test a vehicle security simulation system using facial recognition technology integrated with Arduino Uno and MATLAB. This system utilizes a laptop camera to capture the user's facial image, then performs a detection and verification process using the FaceNet algorithm. If the face is recognized and verified with data stored in the database, the Arduino will activate the actuator components in the form of a DC motor to simulate starting the engine, and a servo motor to simulate opening the vehicle door. This study uses a quantitative experimental approach to analyze the effect of variations in distance (30, 40, and 50 cm) and lighting brightness levels (10–20, 21–30, and 31–40 lux) on the system's response time. A total of 27 combinations of conditions were tested, and the data obtained were analyzed using Microsoft Excel and ANOVA tests in Minitab software. The results of the analysis showed that the optimal response time was obtained at a distance of 40 cm with a medium level of illumination (21–30 lux). In addition, both distance, brightness, and the interaction between the two factors were shown to have a significant effect on the system's response time (P-Value < 0.05). These findings indicate that the system is quite sensitive to environmental changes, so further testing is highly recommended, especially to measure the actual delay, the detection error rate, and the development of a more robust face detection algorithm so that the system can be used reliably in various lighting conditions and face capture angles in the real world.

Dependence on fossil fuels, such as gasoline and diesel, has become a global issue that affects environmental sustainability and energy security. Increasing greenhouse gas emissions, decreasing natural resource reserves, and instability of global energy prices encourage the need for innovation in motor vehicle fuel systems. This study aims to assess fuel efficiency and engine performance on a 110 CC motorcycle with a standard compression of 10.7:1, by utilizing a mixture of RON 90 gasoline and alcohol. The main focus of the study is to compare the effect of varying alcohol content on engine power output, with mixtures of E12.5, E17.5, and E22.5. The method used is an experimental method with three variables, namely the independent variable (type and content of fuel mixture), the dependent variable (engine power), and the control variables (engine condition, temperature, and testing method). Testing was carried out using a combination of iridium spark plugs and standard spark plugs, as well as variations in Pilot Jet sizes 34 and 35 on aftermarket carburetors. Each combination was tested to determine its effect on the maximum engine power. The results showed that a blend of E12.5 fuel with Pilot Jet 35 and iridium spark plugs produced the highest power output compared to other tested combinations. This combination was proven to optimize combustion in the combustion chamber, thereby improving engine efficiency and performance. Conversely, increasing the alcohol content above E12.5 did not provide a significant increase and even tended to decrease power due to alcohol's lower calorific value than gasoline. The conclusion of this study is that the use of an aftermarket carburetor with Pilot Jet 35 and iridium spark plugs, combined with an E12.5 fuel blend, can be an effective alternative for improving the performance of a 110cc motorcycle. These findings are expected to serve as a reference for the development of more efficient and environmentally friendly blended fuel technology.

In the modern era, the need for sophisticated vehicle security systems is increasing along with the high rate of motor vehicle theft. This research designs and implements a fingerprint sensor-based vehicle security system using an Arduino Uno microcontroller. This system aims to improve security by utilizing biometric technology that can only be accessed by verified users. The fingerprint sensor is used to recognize the user's fingerprint, then activate the system through a relay instead of a conventional key. System testing shows a fast response time with an estimated rise time of about 0.5 seconds and settling time of about 2 seconds, without any misidentification (false positive or false negative). Thus, the system is proven to provide higher security, good authentication speed, and ease of use compared to conventional security systems. These results show that the implementation of biometric technology in vehicles has the potential to be widely applied.

Motor vehicle workshops need an information system that can help in managing services, customers, and spare parts stock. This study designs a web-based workshop management system with a case study at the Fam Auto workshop, which aims to improve operational efficiency and data transparency. The methodology used is the waterfall system development model with stages of analysis, design, implementation, and testing. The results of this study are a web-based application that is able to record service transactions, manage customer data, monitor inventory, and generate reports. This system is expected to replace the manual process that has been used at Fam Auto and make it easier for workshop owners to monitor operational activities in real-time.

An increase in the number of vehicles should also be accompanied by improvements in technology that can increase engine efficiency and at the same time reduce air pollution. This research aims to determine the effect of using variations in the number of holes in the injector and the octane number of the fuel on exhaust emissions in motorcycle engines. The research method uses experiments with descriptive analysis. The independent variable is the number of holes in the injector, 4, 6, and 8 and the octane number of 90, and 92. In the exhaust emissions testing process using engine speeds of 1000 rpm, 2000 rpm and 3000 rpm. The bound variable is the emission of carbon monoxide (CO) gas and hydrocarbon gas (HC). Data from CO and HC gas emission testing results at 1000 rpm are all still within the permitted limits. Furthermore, statistical analysis shows that there is an influence of the number of holes in the injector and the octane value of the fuel on CO and HC exhaust emissions and there is no interaction between the octane value variables and the number of injector holes on the CO and HC exhaust gas values. The best results are CO gas emissions = 0.55% and HC = 66 ppm when using a 6 holes injector (standard) and using fuel with an octane value of 92.

One of the impacts of the growth of activities in the transportation sector is the disposal of rubber tire waste. The increasing number of motorized vehicles in society has caused an increase in tire waste. Especially in developing countries, the use of plastic bottles has become an inevitable and unavoidable necessity for society. Inadequate waste management and handling causes negative impacts on the environment, such as hazards to human health, to animal life, soil, water, and air pollution. The purpose of this study was to reduce environmental pollution by testing the compressive strength of concrete made with a mixture of waste. Experiments were conducted in the laboratory with concrete cylinder test objects with a diameter of 150 mm and a height of 300 mm. The proportion of waste mixture, Polyethylene Terephthalate (PET), Rubber Powder, Waste Metalized Film Food Packaging (WMFFP) to fine aggregate was 0%, 5%, and 10%, each variation. The test results showed a compressive strength of 17.62 MPa, 15.29 MPa, and 14.83 MPa at the percentage of waste mixture. From this data, it can be concluded that waste materials can be used as a substitute for sand in concrete.

Intercondylar fractures of the femur are complex intra-articular injuries involving the medial and lateral condyles at the distal end of the femur bone, just above the knee joint. These injuries are commonly caused by high-energy trauma, such as motor vehicle accidents or falls from significant heights. This study presents a case report of a 23-year-old unemployed female patient. The assessment tools used included the Numeric Pain Rating Scale (NPRS) for evaluating pain intensity, a goniometer for measuring the range of motion (ROM), Manual Muscle Testing (MMT) for assessing muscle strength, and the Lysholm Knee Scoring Scale for evaluating functional activity. After three physiotherapy sessions conducted over three weeks, the patient demonstrated a reduction in pain, an improvement in muscle strength, an increased joint range of motion, and enhanced functional activity. A rehabilitation program consisting of Transcutaneous Electrical Nerve Stimulation (TENS), forced knee flexion with a quadriceps board, active knee flexion and extension exercises with a gym ball, stretching exercises, and active functional training was found to be effective in improving the patient's post-operative outcomes following malunion intercondylar femur fracture (right) post-ORIF.

This study aims to describe and analyze: The Effectiveness of Mobile Samsat Services in Serving Motor Vehicle Tax Payments in Lumajang Regency and the factors that affect the Effectiveness of Mobile Samsat Services in Serving Motor Vehicle Tax Payments in Lumajang Regency. The research is a qualitative descriptive analysis. The data analysis technique uses a technique developed by McNabb (2002), namely Grouping the data according to key constructs, identifying bases for interpretation, developing generalizations from the data, Testing Alternative interpretations and Forming and/or refining generalizable theory from case study. The results of the study show that the Mobile Samsat Service has been effective in increasing motor vehicle tax revenue. This program is designed to make it easier for people to pay vehicle taxes, thereby increasing accessibility and convenience. Despite challenges such as technical constraints and time constraints, feedback from the community has been generally positive, stating significant benefits of Samsat Roving in saving time and travel costs. Overall, the Mobile Samsat service in Lumajang Regency has succeeded in creating a mutually beneficial relationship between service providers and customers, which is expected to result in a more positive and trusting relationship between the parties involved. Ease and Accessibility of Services: Taxpayers feel more helped by the services that come directly to them, especially in areas far from UPT offices. The effectiveness of the Mobile Samsat in Lumajang Regency in increasing vehicle tax revenue is influenced by the ease of tax payment, strategic location and operational time, technology adoption, and consistent SOPs. Although it has had a positive impact, continuous efforts are needed to achieve greater inclusivity. These factors are important in improving the effectiveness of vehicle tax services and revenues.