Indiana E-ZPass transponder mounting is a simple process that takes less than five minutes when done the right way. The transponder must sit on the inside of your windshield, about one inch below the roof and one inch to the right of the rearview mirror post. This exact spot gives the toll booth antenna a clear line of sight to read your device every time you pass through a toll plaza on the Indiana Toll Road.
Many drivers miss tolls or get charged the wrong rate because the transponder sits too low, behind tint, or near metal. The good news is the fix is fast. You only need a clean cloth, rubbing alcohol, and the adhesive strips that came with your device. Let me walk through every step so you get a perfect read on your first drive.
What You Need Before You Start
Before you stick the transponder to your glass, gather a few basic items. Most are already in your car or home. Having them ready saves you from stopping mid-process and losing the clean surface you just prepped.
- The E-ZPass transponder with its adhesive strips or Velcro pads still attached
- A microfiber cloth or clean paper towel
- Rubbing alcohol (isopropyl alcohol) in a small spray bottle or on a cloth
- A ruler or measuring tape for accurate placement
- A temperature between 50°F and 85°F in your garage or parking spot for best adhesive grip
Skip the alcohol if you do not have any. Warm soapy water on a cloth also works. Just make sure the glass is fully dry before you press the device on.
The Exact Mounting Position on Your Windshield
Position matters more than most people think. The toll antenna sends a signal from above, so your transponder must sit high on the windshield. It also needs to avoid the black dotted frit band, the rearview mirror, and any tint strip at the top of the glass.
The One-Inch Rule
Place the device one inch below the roofline of your car. The roofline is where the metal top of your vehicle meets the glass. Then move it one inch to the right of the rearview mirror post. If you drive in countries that drive on the left, switch the side. For U.S. drivers, the right side of the mirror post is the standard spot.
Arrow Direction
Look for small arrows on the back or front of your transponder. The arrows must point up toward the roof. This positions the internal antenna to face the toll plaza reader above the lane.
Label Side
The label with your account number and barcode must face you, the driver. Toll workers and police can read it during a stop. The signal still works either way, but this is the legal and practical standard.
Step-by-Step Mounting Process
Follow these steps in order. Do not skip the cleaning step. Dust and oil kill adhesive strength faster than anything else.
- Clean the glass. Spray or wipe rubbing alcohol on a cloth. Wipe the area where the device will sit. Wait 30 seconds for it to dry.
- Mark the spot. Use a small piece of tape or your finger to mark one inch below the roof and one inch right of the mirror post.
- Peel the backing. Remove the plastic film from the adhesive strips on the back of the transponder. Do not touch the sticky side with your fingers.
- Press and hold. Line up the device with your mark. Press it flat against the glass. Hold firm pressure for 30 seconds.
- Wait before driving. Give the adhesive 24 hours to fully bond. Avoid washing the car or rolling the window down in freezing rain during this time.
That is the full process for a standard sedan, SUV, or pickup truck. The device is now active and ready to read at any open toll lane.
Special Windshields and Metallic Coatings
Some cars have windshields that block radio signals. These include vehicles with Solar Tint, Heat Reflective, Insta-Clear, or acoustic glass with a metal oxide layer. If you mount a transponder on these windshields, the toll booth will not read it.
You can test your windshield at home with a piece of aluminum foil. Hold a working transponder behind the foil. If your home reader or a toll simulator cannot pick it up, your car has a coated windshield. The fix is simple: order a License Plate Tag (LPT) from the Indiana Toll Road. The LPT screws onto your front license plate and works exactly like a windshield transponder.
You can request the LPT through your online account or by calling the customer service line listed on the official Indiana Toll Road portal at indianatollroad.org.
Mounting for Motorcycles and Commercial Trucks
Motorcycles use the same transponder as cars, but the placement changes. Mount it on the inner fairing or a flat section of the windshield. Make sure the arrows point up and the device cannot vibrate loose at highway speeds. Some riders use a small zip tie or extra foam padding behind the transponder to stop rattling.
Commercial trucks over 26,000 pounds often need a commercial transponder or a rooftop-mounted unit. These read at weigh stations and high-speed toll lanes. The mounting bracket bolts to the roof or top of the windshield frame. Keep the device within four inches of the centerline of the truck cab. Do not place it next to a light bar, antenna, or air horn, as these create signal dead zones.
Why Your Transponder Might Not Read
Even with perfect mounting, a transponder can fail to read. Here are the most common reasons, ranked by how often they happen.
- Old or weak adhesive. The device tilts forward and the antenna no longer faces up. Re-mount with new strips from customer service.
- Placed on tint strip. The dark band at the top of the windshield blocks the signal. Move it below the tint.
- Behind the mirror. The mirror housing is plastic but still blocks part of the signal. Keep the full one-inch gap.
- Not yet activated. New transponders take 24 to 48 hours to link to your account. Drive through a staffed lane until then.
- Account is out of funds. A negative balance stops the gate from opening. Add money online or at a retail partner.
Relay Attack and Signal Theft Prevention
Modern transponders use encrypted signals, but relay attacks still happen in some areas. A thief near your home uses a device to read and copy your transponder signal while you sleep, then bills tolls to your account. The fix is to store the transponder in a signal-blocking pouch (a Faraday bag) when the car is parked. You can buy these pouches online for under ten dollars. They block the RFID signal until you pull the transponder out for your next drive.
Another option is a metal box or cookie tin. Any fully enclosed metal container works. Just drop the transponder inside when you get home.
Replacing Worn Mounts and Adhesive
Adhesive strips lose grip after two to three years, especially in hot summers. When the transponder starts to slide or tilt, it is time to replace the mount. Do not use super glue or double-sided tape from a hardware store. These can damage the device or leave residue that blocks the signal.
Order official replacement strips through your EZPass account or by mail. The Indiana Toll Road sends free replacement strips to active account holders. Standard hook-and-loop Velcro also works if you want a removable mount. Cut two small squares, stick one to the windshield and one to the back of the transponder, and press them together.
Account Setup and First Use
After mounting, you still need to activate the transponder. Log into your account on the official Indiana Toll Road website and enter the transponder serial number. The number sits on the front label or inside the battery compartment on older models. Once paired, wait 48 hours before driving through an EZ-Pass-only lane. During that time, you can use staffed lanes or pay cash.
Set up automatic replenishment with a credit card or bank account. This stops the most common cause of a failed read: a zero balance at the toll booth.
Quick Mounting Checklist
Run through this list before you press the transponder to the glass. It takes 60 seconds and prevents 90 percent of mounting mistakes.
| Check | Yes / No |
|---|---|
| Glass cleaned with alcohol | |
| One inch below roofline | |
| One inch right of mirror post | |
| Avoids tint strip and black dots | |
| Avoids defroster lines | |
| Arrows point up | |
| Label faces driver | |
| Pressed for 30 seconds | |
| 24-hour cure time planned |
Mark each box. If all nine are yes, your transponder is mounted for a perfect read at every toll booth in the EZ Pass network, including the Indiana Toll Road, the Ohio Turnpike, and the Illinois Tollway.
Official website: https://www.indianatollroad.org/
Customer service phone: 574-675-4010
Hours: Monday through Friday, 8:00 AM to 6:00 PM ET
Address: Indiana Toll Road Concession Company, 52551 U.S. 31, South Bend, IN 46637
Frequently Asked Questions
These questions come from real EZPass drivers on the Indiana Toll Road. Each answer covers a specific issue that regular users face with mounting, reading, and account setup. The answers focus on the exact steps you can take today to fix or avoid the problem.
Can I move my E-ZPass to a second car?
Yes. Pull the transponder off the windshield by pulling straight back on the body, not the adhesive strips. The strips can stay on the glass or come off with a little rubbing alcohol. You can then mount the same transponder in a second vehicle. Just make sure the second car is listed on your account, or the toll will post to the wrong license plate. A single transponder can be used in as many vehicles as you own, as long as each license plate is on the account.
Why does my transponder beep but the gate does not open?
A beep only means the device is powered and detected. The gate opens only when the account is in good standing, the transponder is mounted in the correct position, and the antenna reads the signal. Check your balance first. If the balance is fine, move the transponder one inch up or down and try a different lane. Cold weather can slow the adhesive bond, so give it 24 hours after a fresh mount.
Does the transponder work in a rental car?
Yes. Mount it with temporary adhesive strips or a suction cup holder. The suction cup is the cleanest option because it leaves no mark on the rental glass. Add the rental license plate to your account before driving, then remove it when you return the car. This stops rental tolls from posting to your permanent plates.
How do I know if my windshield blocks the signal?
Hold the transponder against the glass at the spot you plan to use. If you have a portable AM/FM radio, tune it to a quiet frequency and hold the transponder near the antenna. A coated windshield will reduce the signal. You can also call your car dealer and ask if your model has an “acoustic” or “solar” windshield. The dealer will know from the VIN.
Can I put the transponder in my glove box instead?
No. The signal cannot pass through metal or through the dashboard electronics in most modern cars. The toll booth will not read the device. The transponder must be on the inside of the windshield in the clear line of sight of the overhead antenna.
What is the difference between E-ZPass and I-Pass in Indiana?
They work on the same network and use the same technology. The Indiana Toll Road accepts both. Your account, balance, and rules are the same. If you move to Illinois, the same transponder reads at every I-Pass toll booth. You do not need a second device.
Does cold weather affect the adhesive?
Yes. Adhesive strips lose grip below 40°F. If you mount the transponder in a cold garage, bring the car into a heated space for one hour first. This warms the glass and lets the strips form a strong bond. The same rule applies for replacement mounts in winter.