Does ETC have to be attached to the windshield?
4 Answers
ETC can be used without being attached to the windshield. Installing ETC on the upper part of the windshield is to minimize obstruction of the driver's view and to ensure better recognition by highway toll station equipment. If you don't want to install it on the windshield, place it in an open area where it can be seen through the windshield. For small cars, the ETC installation position is generally in the upper middle part of the front windshield, while for large vehicles like trucks and buses, it is installed in the lower middle part. The appropriate installation position is at a height not lower than 1.2 meters and not higher than 2.5 meters, with an installation angle between 30 to 90 degrees. For vehicles with anti-explosion film or those that have it installed later, which may affect microwave communication signal transmission, ETC should be installed in the microwave window zone. Here are some precautions for installing ETC: Do not block the view; it's best to install it behind the rearview mirror: Many car models have windshields with a large rear tilt angle, which reduces the driver's field of vision. If ETC is installed without considering this, it may increase the driver's blind spots. Installing it behind the rearview mirror on the right side can help avoid obstructing the view. Do not interfere with charging: The ETC electronic tag consumes power but generally does not require charging or battery replacement because it has a solar panel on the back for self-charging. Therefore, during installation, avoid the black areas on the windshield and positions that may block the solar panel. Do not remove it casually once installed: The button in the middle of the adhesive is an anti-removal rod connected to a switch. After installation, the windshield will press the anti-removal rod in. If removed casually, the rod will pop out and trigger the switch, locking the electronic tag and rendering it unusable. You will then need to visit an ETC service point to unlock it. This mechanism is designed to prevent multiple vehicles from sharing one device. Notes for using ETC: The ETC transaction sensing range is 8 meters. To prevent issues with the ETC device of the vehicle in front, maintain a distance of more than 10 meters from the vehicle ahead to avoid automatic payment for the front vehicle. The speed limit for ETC lane recognition is 20 kilometers per hour. Driving too fast may result in failure to read vehicle information and unsuccessful fee deduction. When using a debit card linked to ETC, insufficient balance may also cause payment failure.
As a frequent driver, I don't think the ETC must be stuck on the windshield, but the official recommendation is to place it there for optimal stability. I've driven different types of vehicles, and sometimes the windshield has sunshade film or is too slippery, making the ETC affect aesthetics or prone to falling off. In such cases, a dedicated bracket can be used to fix it on the dashboard—for example, a plastic bracket with double-sided tape—and the signal still works, though occasionally slower or even failing at toll stations. Once, I experimented by not placing it on the windshield, and the toll station failed to detect it, forcing me to queue for manual processing. From a practical perspective, the windshield position provides the strongest signal because the antenna faces outward directly with minimal metal interference. Other positions, like the dashboard, weaken signal penetration due to the windshield, reducing recognition rates; hiding it inside the car is even worse. Unless there are special circumstances, such as a damaged windshield, I suggest properly sticking it in place to avoid trouble and extra delays. Regularly checking the installation's firmness is also important to prevent device wobbling.
The working principle of ETC involves RFID signal interaction, and the ideal location is the windshield as it provides a good signal channel and antenna protection. However, in practice, it doesn't necessarily have to be attached to the glass. For example, if the car design is special or there is interference from other devices, a bracket can be used to install it in the central control area, and plastic surfaces with minimal metal components can maintain basic functionality. I've seen a friend use hook-and-loop fasteners to secure the ETC under the sun visor, where signal reception is barely feasible but stability is poorer. Windshield materials like heat-insulating films can affect signal transmission efficiency, causing delays at toll booth scans. The official specifications of the device emphasize installation height and direction, and arbitrary changes carry significant risks. Overall, from a reliability standpoint, glass mounting is the preferred choice; tests show that non-standard locations increase the probability of failure. For smooth driving, sticking to the recommended solution is the wisest choice.
ETC offers high convenience, allowing fast passage through toll stations and saving time. The installation location has minimal impact, but experience tells me that attaching it to the windshield provides more peace of mind. Placing it elsewhere, such as on the dashboard, may cause the device to shift due to bumps, leading to unstable signal strength. I once tested using a mount, and the recognition rate dropped during harsh weather. The official design is based on windshield standards, so altering the location requires caution to avoid metal obstructions. It is recommended to attach it properly to prevent issues.
