Must ETC be installed on the windshield?

[MaggieLynn]

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 while ensuring better recognition by the toll station equipment. If you prefer not to install it on the windshield, place it in an open area where it can be seen through the windshield. For small vehicles, 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 suitable installation height is between 1.2 meters and 2.5 meters, with an angle between 30 to 90 degrees. If the vehicle has or will have a sunshade film, which may affect microwave signal transmission, it should be installed in the microwave window area. Here are some ETC installation precautions: Do not obstruct the view; installing it behind the rearview mirror is ideal: Many car models have windshields with a steep angle, which can reduce the driver's field of vision. Installing ETC without considering this may increase 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 requires power but generally does not need charging or battery replacement, as it has a built-in solar panel for self-charging. Therefore, avoid installing it on the windshield's shaded areas or where the solar panel may be blocked. Once installed, do not remove it arbitrarily: The adhesive button in the middle is an anti-tamper lever connected to a switch. After installation, the windshield presses the lever in. If removed, the lever will pop out, triggering the switch and locking the tag, requiring an ETC service point to unlock it. This prevents multiple vehicles from sharing one device. ETC usage notes: The ETC transaction sensing range is 8 meters. To avoid issues caused by the vehicle ahead, maintain a distance of over 10 meters to prevent automatic payment for the wrong vehicle. The ETC lane recognition speed is 20 km/h; exceeding this speed may result in failed transactions. If using a debit card linked to ETC, insufficient balance may also cause payment failure.

[AdrielLee]

The other day when I installed my ETC, I also wondered why it had to be stuck on the windshield. The technician told me it's mainly for signal reception. The black dotted area near the rearview mirror in the center of the windshield is the golden spot—closest to the toll station antenna, and the solar panel gets full charge. My neighbor didn’t believe it and stuck the ETC on the dashboard, but ended up having to reverse and rescan at every toll gate. Eventually, he obediently moved it back. When installing, remember to avoid areas with metal film, as it can block the signal. Now, highway trips are smooth as silk, so I suggest everyone install it in the standard position.

[PenelopeDella]

Seeing your discussion about ETC installation locations, let me share some practical insights. The windshield is indeed the officially recommended spot, but the fundamental reason lies in signal transmission principles. Those small black grids are actually the optimal path for the antenna reception window, with low metal content and minimal interference. Last year, I tried installing it on the rear windshield, but it failed to scan three out of five times. Relocating it to the lower right corner of the windshield worked for recognition, but the adhesive melted under direct sunlight. Later, I found the middle of the front windshield to be the most stable—zero failures over three years. Just be careful not to block the interior rearview mirror; safety comes first.

[LeArabella]

Last time when helping a friend install an ETC device, I specifically studied the manual. The windshield is indeed the mandatory installation location, mainly because there's an anti-removal switch at the bottom of the device. Once peeled off the glass, that small spring will pop out and lock the device. I learned this the hard way when trying to move it to the dashboard as a temporary parking card—ended up completely disabling the whole unit. Reactivating it required a trip to the bank, which was a huge hassle. My advice: clean the windshield thoroughly before installation; peeling off a misaligned sticker tends to leave adhesive residue. If you're really unsure about the placement, just check where new cars have them pre-installed from the factory—that spot is always correct.