The first U.S. demonstration of a smartphone tolling app on a live state-managed tolled facility — independently evaluated by CDM Smith, presented to Governor Ferguson and the Washington Senate and House Transportation Committees, January 2026.
We see it as a very viable and complementary way of advancing tolling into the future.
Reema Griffith
The Washington State Transportation Commission was directed by the 2025/27 Transportation Budget Proviso (Section 205) to "conduct pilot or pilots of advanced tolling technology provided by the private sector" — to assess viability and accuracy of technologies that could reduce implementation costs or enable more flexible operations. WSTC ran a global scan, selected GoCarma, recruited Good To Go! customers, and delivered findings to the legislature on schedule.
The accuracy delta between Bluetooth-paired and unpaired devices is the single most actionable finding of the pilot. With pairing, the app performed at near-perfect accuracy. Without pairing, it dropped to 64% — but the fix is a one-time onboarding step, not new infrastructure.
Single-point tolling on a busy, currently-tolled bridge. Segment tolling on an untolled mountainous corridor with limited cell coverage. The pilot stressed both ends of the deployment spectrum.
Tested at the existing gantry on the SR 520 floating bridge across Lake Washington — between Seattle and Bellevue. Compared GoCarma's smartphone tolling against the existing Good To Go! all-electronic toll system, in parallel, on the same drivers.
A 7-mile mountainous segment of SR 18 just south of I-90 — currently not tolled, frequent serious accidents, and known to have inconsistent cell signal. Stress-tested smartphone tolling where the conditions are worst.
A geo-fenced virtual zone, sized to the corridor, defines where the app pays attention. Outside the zone, location collection is off. Inside, the transaction completes through WSDOT's existing back-office — no gantries, no new readers, no driver interaction.
Drivers raised 401 support issues during the pilot — most about app setup and Bluetooth pairing. The in-app chatbot resolved 358 of them without a single staff conversation. Only 43 required employee action. That's the cost-to-collect story in one number.
This is the call-center economics that makes smartphone tolling viable at scale. The same chatbot can sit in front of every WSDOT toll customer, paired or not — independent of any decision about a future smartphone-tolling rollout.
CDM Smith's recommendation, the WSTC's recommendation, and the legislative direction all align: pilot graduates to a full operational test that combines the smartphone app with roadside vehicle detection to backstop unpaired trips. Phase 2 is under legislator consideration as of 2026.
Carma's work on SR 520 didn't start in 2025. It started in 2010 — before tolling existed on the bridge — when WSDOT brought Avego (Carma's predecessor) to Seattle to deploy real-time carpool ride-matching on the corridor as a way to reduce congestion. Microsoft was a partner. A dedicated Windows Phone version of the app shipped alongside the iPhone build to put it in employees' hands at Redmond. Fifteen years later, the same corridor is the proving ground for smartphone tolling.
