PURPOSES : Unlike European standards, domestic performance assessment standards for truck mounted attenuators (TMAs) was first stipulated in 2014 using the NCHRP Report 350 of 1993 as the standard instead of the 2009 MASH of the United States. The purpose of this study is to present an improvement in the domestic performance evaluation criteria for TMAs.. METHODS : Considering the latest TMA performance evaluation standards in the U.S. and Europe, domestic performance evaluation criteria must improve stipulations related to impact speeds, impact conditions, impact cars, and support trucks. The performance change in the TMAs according to the variation in the impact speed, impact condition, impact vehicle, and support vehicle was investigated using finite element analysis (FEA). RESULTS : The TMA for an impact speed of 100 km/h showed a limit to the safety of the occupants of the collision vehicle and workers on the road for a collision speed of 120 km/h. The safety of the workers on the road was also not guaranteed for the collision of the remaining 73.8% of vehicles that exceeds the maximum impact car weight of 1,300 kg, the lower 26.2% of the total mass composition of domestic passenger cars. In addition, a TMA that satisfied only the conditions under which the vehicle was hit head-on to the center of the TMA did not reduce the risk of a secondary collision of the impact vehicle. Furthermore, the safety of workers on the road was not guaranteed when a travel distance of a support truck of 10 tons or more was applied to a work vehicle of less than 10 tons. CONCLUSIONS : To improve the safety of road traffic, a performance level corresponding to an impact speed of 120 km/h was added to the domestic TMA performance evaluation standard, and the eccentricity and oblique collision conditions were mandatory. Furthermore, the maximum impact vehicle weight of 1300 kg was raised to 2000 kg, and the test requester had to present support trucks of lower and upper weights such that TMA mounting trucks of various weights could be used.

PURPOSES : The purpose of this study is to disseminate the process of deriving the truck performance curve of Korea’s representative trucks in detail such that the relevant experts can use it in the future when re-selecting the representative trucks and deriving the truck performance curve accordingly. METHODS : To collect relevant data required to derive the truck performance curve, this study used four trucks that implemented the weight/power of the nation’s representative trucks, and conducted a practical driving test on four different upgrade sections. RESULTS : The truck performance curve was derived for each driving position to represent the deceleration and acceleration capabilities of the truck through the actual driving test on the upgrade sections. CONCLUSIONS : The truck performance curve derived from this study indicated that the truck’s deceleration and acceleration capabilities increased as the total weight/power of Korea’s representative trucks improved, and the design of the climbing lane demonstrated that the design method used in this study saved approximately 60% of the construction cost compared to the existing method.

PURPOSES : The purpose of this study is to revise the weight to power ratio of the representative truck in S. Korea. So far, S. Korea has been using the unit lb/hp, and the construction machines were not considered in the evaluation of the performance of trucks. METHODS : This study was performed to recommend the use of ISO system of units, and to analyze the weight to power ratios of the representative trucks in S. Korea, including the dump trucks, concrete mixer trucks, and asphalt and concrete diffusers. RESULTS: From this study, the 85 percentile value of the weight to power ratio of the trucks in S. Korea’s was found to be 103.6 kg/kw. CONCLUSIONS : The performance standard for the representative truck has to be increased upward, considering the travel pattern of the dump trucks, concrete mixers, and asphalt and concrete diffuser trucks, travel distances, narrow area (work zone) of operation, and the saving in construction budget for climbing lane. Based on this study, the weight to power ratio of the representative truck in S. Korea could possibly be revised to 100~110 kg/kW.