How Road Charge Pilot works
A plain-language walkthrough of what happens behind the scenes.
1. Detecting a chargeable zone
Each chargeable zone we track (a Clean Air Zone, ULEZ boundary, toll road, or a barrierless crossing like a bridge, tunnel or airport zone) has a boundary built into the app. Road Charge Pilot uses your phone's location in the background to watch for you approaching one of these areas, without you needing to open the app or start anything manually.
Right now that's London's Congestion Charge, LEZ and ULEZ, the Bath, Birmingham, Bradford, Bristol, Newcastle/Gateshead, Portsmouth and Sheffield Clean Air Zones, Oxford's Zero Emission Zone and traffic filters, Scotland's Low Emission Zones (Aberdeen, Dundee, Edinburgh and Glasgow), Dartford Crossing, Humber Bridge, Mersey Gateway, the Sandbanks Ferry, Silver Jubilee Bridge, the Silvertown & Blackwall Tunnels, Tyne Tunnel, Warburton Bridge, and drop-off zones at Birmingham, East Midlands, Gatwick, Heathrow, London City, London Southend, Luton, Manchester and Stansted airports. Worth knowing if you drive for work: most Clean Air Zones only charge taxis, PHVs, vans, buses/coaches and HGVs, not private cars (Portsmouth's is narrower still, only charging taxis/PHVs and buses/coaches/HGVs) and London's LEZ (a separate, older scheme from ULEZ) only charges vans/minibuses and HGVs/buses/coaches, not taxis, PHVs or private cars at all. The app takes your vehicle type into account, so you get the result that's actually correct for that zone rather than a one-size-fits-all guess.
Scotland's Low Emission Zones work a little differently: instead of a daily charge, a non-compliant vehicle risks a Penalty Charge Notice (PCN) from the council, sent by post, so there's no "pay by" date the app can show you with certainty, since councils have up to 28 days to issue one. We show an estimated date instead and explain the real process, rather than pretending a bill exists before it does.
Oxford's traffic filters work in a similar way. There's nothing to pay: a car without a permit that drives through one may be sent a warning notice or a fine by post, and the app tells you when that might have happened. Vans, motorbikes, lorries and buses can use the filters freely.
To save your battery, the app doesn't track your precise location constantly. It uses efficient, low-power geofencing to notice when you're getting close to a zone, and only switches to more precise GPS tracking once you're near enough that a crossing is actually possible. Once you're confirmed to have left the area, it steps back down to low-power monitoring again.
2. Confirming a crossing
When your precise location is confirmed inside a zone's real boundary, Road Charge Pilot logs a "crossing" and sends you a notification straight away, telling you which zone you've entered and whether a charge is likely to apply to your vehicle.
It also checks how you're travelling. If your phone's motion sensors show you're walking, running or cycling (a foot passenger on the Sandbanks Ferry, say, or a walk round a city centre), it isn't counted as a crossing, so you won't get a charge alert for a vehicle you aren't in. If it isn't clear how you're travelling, you'll get the alert anyway: an unnecessary alert is better than a missed charge. Buses and trains look like any other vehicle to your phone, so you may still get an alert as a passenger. This uses Motion & Fitness access on iPhone, or Physical activity access on Android.
3. Checking your vehicle
Whether a charge applies usually depends on your vehicle's fuel type and emissions standard. When you add a vehicle, Road Charge Pilot looks it up using your registration number against DVLA's official vehicle data, including its emissions standard and tax status.
If a lookup isn't available (for example if the registration can't be found, or you'd rather not use it), you can instead enter your vehicle's fuel type and date of first registration. We use the same statutory date bands that TfL's own ULEZ checker uses to estimate an emissions standard from that. It's clearly labelled as an estimate, since we can't verify it the way a DVLA lookup does, but it's the same fallback method the official checkers use.
4. Paying in time
Most chargeable zones work "in arrears": you drive through, then have until a deadline (often midnight the next day) to pay. Every crossing Road Charge Pilot logs shows its payment deadline, gives you a quick link to pay through the relevant scheme operator, and lets you mark it as paid once you have, so your list only ever shows what's still outstanding.
If a crossing is still unpaid as its deadline gets close, you'll get a reminder. By default that's at 6pm on the day it's due, and under Alerts & Notifications in the app you can change the time, add up to five reminders (the evening before, for example) or turn them off. Reminders are set on your phone, so they arrive even with no signal, and they stop as soon as you mark the crossing as paid. Tap one to go straight to the payment page.
What we don't do
Road Charge Pilot doesn't pay any charge on your behalf, and it isn't a guarantee of compliance. See our Terms of Use for the full detail. It's a heads-up, not a substitute for checking with the zone operator if you're ever unsure.
Curious about what we collect to make this work? Read our Privacy Policy.