The purposes of this research were: 1) to study the effectiveness of customer relationship management influence the customer trust on service quality on private vehicle inspection service in Phra Nakorn Si Ayutthaya 2) to study the customer loyalty influence the customer trust on service quality on private vehicle inspection service in Phra Nakorn Si Ayutthaya. 3) to study the effectiveness of customer relationship management influence the customer loyalty on private vehicle inspection service in Phra Nakorn Si Ayutthaya. The samples in this study were 325 Banpan private vehicle inspection service’s customers in Sena district Phra Nakorn Si Ayutthaya province. The data were analyzed by using frequency percentage mean standard deviation and Multiple Regression Analysis. The results found that the opinion levels on effectiveness of customer relationship management in overall and each aspect was found that the customer engagement customer hearing customer suggestion customer retention and customer prospecting were at the high level. The opinions level toward the customer trust on service quality was found at highest level in overall. The opinions level toward the customer loyalty was found at high level in overall. The result of hypothesis test found that the effectiveness of customer relationship management in customer suggestion customer retention and customer prospecting were influenced the customer trust on service quality. However the customer engagement and customer hearing were not influenced the customer trust on service quality. The customer trust on service quality were influenced the customer loyalty. The effectiveness of customer relationship management in customer engagement customer suggestion customer retention and customer prospecting were influenced the customer loyalty however the customer hearing were not influenced the customer loyalty.

Border crossing trade can an important role in the competitiveness of Thai products in neighboring countries as Thailand has a geographical advantage that connects with neighboring countries making border trade an important part of generating revenue for the country. Thailand - Malaysia border trade study showed that the transit process took a long time resulting in a waiting truck at the checkpoint causing traffic jams and the congestion and congestion of the customs. As a result the average waiting time of the system takes up to 264.19 minutes per trip and transportation cost from 7141.87 baht per trip by reducing the waiting time from the process to 13.41 minutes per trip it was found that the transportation cost was 6975.16 baht per trip (Decrease of 166.71 baht). Reduction the transportation costs and waiting times enhance the potentiality and the competitiveness of border crossing

The aim of this research is to create the center of mass testing machine for vehicles with maximum mass 3000 kilograms. By the performance of this machine is able to determine the center of mass 3 axis by horizontal longitudinal and vertical. On the other hand the verities of mass from 50 to 100 kilograms and the several of weight distribution at horizontal and longitudinal are applied to the condition of testing for reasonable to the position of the center of mass. The result of research discovered to the performance of center of mass tester was activated following to test conditions. Furthermore the weight distribution at longitudinal was the highest effect to the horizontal center of mass. By the way the value of weight distribution at horizontal is more effects to the longitudinal center of mass. Moreover increasing of mass was impact to the vertical center of mass and it’s independent to the position of weight distribution.

The aim of this research is to study the varieties of weight density distribution affect to the center of mass and vehicle stability. The weight density distribution tester was designed and changed the position of mass. Base on the center of mass is main points of vehicle stability. On the other hand FMCSA standard was applied to field test for considering of the brake performance and vehicle stability. The results of research discovered to the mass distribution on longitudinal plane are affected to the center of mass and absolutely influence at the right wheel on the front axle. In term of the braking performance it’s depends on the lateral mass distribution especially the center position of mass installed on longitudinal and horizontal plane and close up on the front axle (Y2). For the vehicle stability results the position (Y2) is the highest influence for yaw rate and sideslip. Otherwise the position (Y3) or the position of mass installed on longitudinal plane and nearly at the left wheel on the rear axle. Additionally wheel lock-up condition was appeared on the front axle only. Because the behavior of weight distribution on the front axle was decreased lead to mass distribution on longitudinal plane.

The aim of this research is to study the brake proportional affected to vehicle stability. Braking performance and vehicle stability testing are the main of research purposes. Otherwise learning research center and new researcher in automotive engineering are the minor research objectives. The results of research discovered to the braking performance depend on driver behavior. By the minimum deceleration was appeared on the non-proportion in front axle with braking ratio 0:100. In term of vehicle stabilities yaw and pitch moment are normally occur by the driving behavior. But the sideslip is an absolutely effect to vehicle handling. With the braking ratio 100:0 there is the highest risk for controlling a vehicle cause of the wheels were locked-up condition in the rear axle. Therefore the value of the sideslip was exceeded with the criteria. Furthermore these project researches were got the learning research center and the new researcher in automotive engineering field.