Colorado has two main toll roads, and payment methods differ by road

Colorado operates two toll roads: I-25 in the Denver metro area (the T-REX project corridor) and US 36 between Denver and Boulder. Both roads use electronic tolling, meaning you cannot pay with cash at a booth. You must either have a transponder account set up in advance or pay by mail after receiving an invoice.

The roads are managed by the Colorado Department of Transportation (CDOT), but payment is handled through a private contractor. How you pay depends on whether you have a transponder, whether you live in Colorado, and which road you use.

Key Takeaways

  • I-25 and US 36 tolls are collected electronically; you cannot pay cash at a toll booth.
  • You can pay with a transponder account, a rental car toll pass, or by invoice after you drive.
  • Colorado residents and out-of-state drivers have different payment options and discount levels.
  • If you receive an invoice in the mail, you must pay within 30 days to avoid late fees and penalties.
  • Transponder accounts require a valid driver's license and vehicle registration to set up.

Setting up a transponder account for regular toll use

A transponder is a small electronic device you mount on your windshield that automatically charges your account as you drive through tolled sections. This is the fastest and cheapest way to pay if you use the roads regularly. Colorado residents get a discount on tolls when using a transponder; out-of-state drivers pay the full rate.

To open a transponder account, visit www.coloradotollbyplate.com or call the toll authority directly. You will need your driver's license number, vehicle registration, and a valid payment method (credit card or bank account). You can choose to prepay a balance or set up automatic payments when your account runs low.

Once your account is active, the transponder arrives by mail within 7 to 10 business days. Mount it on the inside of your windshield, centered and above the rearview mirror. The transponder reads automatically as you pass through tolled areas.

Paying tolls without a transponder

If you do not have a transponder, the toll system reads your license plate as you drive through. You will receive an invoice by mail within two weeks. The invoice shows the date, time, location, and toll amount for each trip.

You must pay the invoice within 30 days of the invoice date. Pay online at the same website (coloradotollbyplate.com), by phone, or by mail. Without a transponder, you pay the full toll rate with no discount, and there is an additional administrative fee added to each trip (the amount varies but is typically a few dollars per transaction).

If you do not pay within 30 days, late fees and penalties begin to accumulate. Unpaid tolls can eventually result in vehicle registration holds, meaning you cannot renew your registration until the debt is cleared.

Renting a car and paying tolls

If you rent a vehicle in Colorado, the rental company will offer you a toll pass option at pickup. This is usually a one-time fee (typically $15 to $25) that covers all tolls during your rental period, with the rental company billing your credit card directly.

If you decline the rental toll pass, you are responsible for any tolls incurred. The rental company will forward your information to the toll authority, and you will receive an invoice by mail. This route is more expensive because you pay the full rate plus the administrative fee for each trip.

Ask the rental agent whether the toll pass covers both I-25 and US 36, or only one road. Some passes are limited to a single corridor.

Discounts and rates for Colorado residents

Colorado residents with a transponder receive a discount on tolls compared to out-of-state drivers. The exact discount percentage varies by time of day and road congestion. Peak-hour tolls are higher than off-peak tolls on both roads.

To receive the resident discount, your transponder account must be registered to a Colorado address and linked to a Colorado driver's license and vehicle registration. If you move out of state, you must update your account or you will lose the discount.

Out-of-state drivers and drivers without a transponder pay the posted toll rate plus administrative fees. There is no discount available for these payment methods.

What to do if you receive a toll invoice

Open any invoice you receive from the toll authority promptly. The invoice will show the toll amount, the administrative fee (if applicable), and the due date. You have 30 days from the invoice date to pay.

Pay online at coloradotollbyplate.com using a credit card or bank account. You can also pay by phone at the number listed on the invoice, or by mail if you prefer to send a check. Keep a record of your payment confirmation.

If you believe an invoice is incorrect—for example, if you did not drive that route or the amount seems wrong—contact the toll authority before the due date. Disputes can take time to resolve, so do not ignore the invoice while waiting for a response.

Penalties for unpaid tolls and how to resolve them

If you do not pay an invoice within 30 days, the toll authority adds a late fee to your account. If the debt remains unpaid for several months, additional penalties and collection fees may be added. The total amount owed can grow significantly.

Unpaid toll debt can result in a registration hold, which prevents you from renewing your vehicle registration. You cannot legally drive the vehicle once your registration expires. To clear the hold, you must pay the full amount owed, including all fees and penalties.

If you are unable to pay the full amount, contact the toll authority to ask about payment plans. Some situations may may have access to for a reduced payment arrangement, though this is not may provide. The sooner you contact them, the more options may be available.

Frequently Asked Questions

Can I use a transponder from another state on Colorado toll roads?

No. You must set up a Colorado toll account through coloradotollbyplate.com. Transponders from other states will not work on I-25 or US 36. If you live out of state and drive these roads regularly, you can open an account and have a transponder mailed to you.

What happens if I lose or damage my transponder?

Contact the toll authority to report it. You can request a replacement transponder, which will be mailed to you. Until it arrives, your account will still work if the toll system reads your license plate, though you will pay the administrative fee for each trip.

Do I have to pay tolls if I only drive one exit on a tolled road?

Yes. Tolls are charged for any use of the tolled sections, even if you only drive a short distance. The toll amount is based on the distance traveled and the time of day, not the length of your trip.

Can I get a refund if I overpay my toll account?

Yes. If your prepaid balance exceeds what you owe, you can request a refund through your online account or by contacting the toll authority. Refunds are typically processed within two to four weeks.

What if I drove the toll road before I knew about the tolls?

You will receive an invoice by mail. Pay it within 30 days to avoid late fees. If you have questions about specific charges, contact the toll authority with the dates and times of the trips in question.