# Comparative Accuracy Analysis of Truck Weight Measurement Techniques
## 5 Conclusions  
The development of weighing vehicle systems provides a tool to measure the impact of live load on road infrastructure. This knowledge is helpful in the management of roads and bridges, in the design, evaluation, maintenance, and improvement. Accurate and reliable measurements allow for a better estimation of the traffic-induced effects. There are new opportunities to use non-invasive weigh-in-motion systems, which do not interrupt and delay traffic and road infrastructure. Weigh-in-motion systems can continuously collect traffic weight data. In this study, the static and dynamic vehicle weight measurements were compared to assess the accuracy of the measurements. Four weigh measuring systems were considered: portable scales, truck weigh station, WIM, and B-WIM. About 150 trucks were measured, and statistical analysis was conducted to compare the differences between the measuring systems by multiple _t_-tests, ASTM E1318-09 [29] tolerance check, and correlation coefficient calculation. Based on this study, it can be concluded that the certificated portable scales are accurate but cumbersome in operation, and the measurements are time-consuming. Furthermore, operators and drivers have to be involved. This is a selective method that only captures selected vehicles, however, because of accuracy, they were used as a reference point in _t_-test and tolerance analysis. The portable scale measurements were compared to the truck weigh station. The tolerance comparison indicated 92-99% of tolerance for measured attributes. The linear correlation coefficient varies from 0.64-0.80, proving the strong correlation between the measurement by both static scales. Truck weigh stations also provide accurate results, but their operation is expensive and, therefore, inefficient. Moreover, their location is well known, and haulers of illegally overloaded vehicles can find alternative routes and avoid being ticketed. The weigh station measurement was used as a reference point for weigh-in-motion measurements. Additionally, truck weigh station measurements were compared with portable scales, where tolerances between the analyzed vehicle attributes vary from 84-100%. It provided good results, but some of the measurements are below the required 95% compliance level. Weigh-in-motion data can continuously measure vehicle attributes, which allows the collection of massive traffic data. The WIM data measurement tolerances were compared to portable scales, where 92-98% of the measurements were within the tolerance level. Only the second tandem axle provides 87% tolerance of the measurements. Throughout the analysis, axle 4 th and 5 th, and accordingly, the second tandem axle provide the lowest tolerance margin. The tolerance measurements in comparison to truck weigh stations were between 84-96%. Compared to portable scales, the linear coefficient of correlation varies between 0.60-0.76, which provides a moderate/high correlation. For the truck weigh station, its coefficient is 0.45-0.52, which presents a modest correlation. B-WIM system is an efficient tool to measure bridge response to truck traffic. The results show that B-WIM provides reliable measurement data. The measured tolerances are between 90-98% compared to portable scales and 88-97% compared to truck weigh station. The correlation coefficient is 0.67-0.87 for portable scales and 0.59-0.77 to weigh station. That shows a high correlation and proves weight measurement's reliability. Moreover, the multiple \(t\)-test analysis was conducted to verify whether the measurements are different for a 95% confidence interval. It was proved that, for 95% confidence, the results are statistically different. If the tolerances are considered, it can be concluded that most of the measured vehicle attributes provide accurate results that meet the ASTM requirements. This study's constraints include the sample size, consideration of only 5-axle vehicles.