On the national highways, the current ETC service operator uses both Infrared DSRC and RFID technologies simultaneously to collect toll fees. At the front-end of the ETC system, the identity of an IR-DSRC OBU is detected and the fee charged is deducted from the e-purse directly if available, while the identity of an RFID eTag is detected and used for deduction from a registered account afterwards. Meanwhile, video images are taken and used in the backup procedure for identifying vehicles without payments, and a back-end management procedure completes the charging mechanism. The success of this mechanism is based on a high correctness rate of the wireless communication system, or the burden in the backup procedure needs more manpower to check the video images and inform the unpaid car owners. The more manual works, the more operational costs. Though RFID technology is now widely used in logistics, parking and human management, where passive tags has some advantages with a low price and a compact size, it has some issues on frequency allocation, interference, and e-safety, etc. When Taiwan wants to use the eTag for the mileage-based toll collection nationwide, other areas or countries have issued their own ETC standards using 5.8 GHz DSRC. This paper will introduce the international trend on 5.8 GHz DSRC, and will show the studying results on this technology for the single-lane and the multi-lane-free-flow scenarios.