THE CHALLENGEA Car-Sharing Car Has to Trust a Stranger's Phone
Car-sharing only works if a member can walk up to any vehicle, unlock it with their phone, drive, and walk away, with the booking, the billing, and the security all handled in the background. That means the in-car box has to talk to the CAN bus to lock and immobilise, hold a secure BLE and UWB link to the phone, meter usage precisely, and never strand a member or leave a car open. Most operators stitch a generic tracker to an off-the-shelf app and hit a wall on keyless access and billing accuracy. The telematics control unit, the digital key stack, and the booking platform are designed together so access, security, and metering all line up.
Part of the Telematics and GPS Tracking stack, and commonly built alongside Digital Key Telematics.
WHAT'S INCLUDED
The Car-Sharing Control Stack
In-Car Telematics Control Unit
The telematics box is designed around an automotive-grade STM32 or i.MX processor with a CAN and OBD-II interface to the vehicle. It controls central locking, reads ignition and odometer, and arms or releases the immobiliser, all over a hardened link to the cloud.
Keyless Access with BLE and UWB
The digital key stack turns a member phone into the key. BLE handles pairing and presence, and UWB adds secure ranging so the car only unlocks when the phone is genuinely next to it, defeating relay attacks. A backup PIN or card keeps a member moving if their phone dies.
Booking and Billing Integration
The platform connects to your reservation and payment systems so a booking reserves a specific car, the in-car box accepts only the booked member, and usage closes out into an invoice automatically. Pre-authorization, per-minute or per-hour rates, and fuel or charge fees all reconcile against real vehicle data.
Immobiliser and Theft Protection
Immobiliser control runs over CAN so a car outside a valid booking cannot be driven away. Tow detection, unexpected movement, and ignition without a booking raise alerts and can hand off to a stolen-vehicle recovery flow.
Usage Metering
Trips are metered precisely from odometer, ignition, and GPS data so billing is fair and auditable. Distance, duration, idle time, and zone of use all feed the invoice, and a clean trip record settles disputes without a phone call.
Fleet Operations Platform
The operator view spans the whole fleet: vehicle availability, fuel and charge state, cleaning and service flags, and damage reports tied to before and after photos. Operations can take a car off-rent, dispatch a cleaner, or rebalance with two clicks.
THE BOOKING, START TO FINISH
Reserve, Unlock, Drive, Return
A member should never touch a physical key or wait at the car. Behind that simplicity sits a chain of secure handshakes between the booking system, the phone, and the in-car box. Each link is built so the experience stays smooth and the security stays tight.
Reserve a Specific Car
The booking reserves one vehicle and issues a time-bounded digital key to the member phone. The in-car box receives the booking window and the member credential over MQTT before the member arrives.
Unlock by Presence
At the car, BLE detects the phone and UWB confirms it is actually beside the vehicle. The box releases central locking and the immobiliser only for the booked member, only inside the booking window.
Return and Auto-Invoice
On return the member locks the car from the app, the box re-arms the immobiliser, and the trip closes out from odometer and time data into an automatic invoice. The car returns to the map for the next booking.
HOW IT WORKS
From CAN Bus to Cloud
In-Car Firmware
FreeRTOS or embedded Linux runs the CAN and OBD-II interface, the BLE and UWB key stack, and the secure element that stores keys. Lock, immobiliser, and access decisions are made locally so the car responds instantly even with a weak network.
Connectivity and Security
The box uses a Quectel EC200 or u-blox LTE module with MQTT over TLS for telemetry and commands. Digital keys live in a secure element, commands are signed, and UWB ranging blocks relay attacks that defeat BLE-only systems.
Cloud Platform
A booking service, a billing engine, and a fleet operations layer share one vehicle data model. Reservations issue and revoke keys, usage metering feeds invoices, and operations watch fuel, charge, and service state across the fleet.
SECURITY AND COMPLIANCE
Built to Protect the Asset
Automotive Integration
Integration over standard CAN and OBD-II is validated against the vehicle networks of your fleet, so lock, immobiliser, ignition, and odometer behave correctly across mixed makes and models without disturbing factory systems.
Key and Data Security
Digital keys are held in a secure element, every access command is signed, and UWB secure ranging defeats relay attacks. Telemetry runs over TLS and member data handling follows GDPR and local privacy rules.
Payment Compliance
Billing runs through PCI-compliant processors with pre-authorization and audited usage records. A complete, tamper-evident trip log makes every invoice defensible and keeps chargebacks low.
FAQ
Common Questions
How does keyless access work in your platform?
A member phone becomes the key through a digital key stack. BLE handles pairing and presence, and UWB adds secure ranging so the car only unlocks when the phone is genuinely beside it. Keys are time-bounded to the booking and stored in a secure element, with a PIN or card backup if a phone dies.
Why use UWB alongside BLE?
BLE alone can be fooled by a relay attack that extends the apparent range of the phone. UWB measures the true distance between the phone and the car, so access is granted only when the member is actually present. The two are paired for fast, secure entry.
How is a car stopped from being driven outside a booking?
Immobiliser control runs over CAN. Outside a valid booking the car cannot be driven, and ignition without a booking, tow detection, or unexpected movement raises alerts that can hand off to a stolen-vehicle recovery flow.
How accurate is usage metering for billing?
Metering reads odometer, ignition, and GPS data directly from the vehicle, not from estimates. Distance, duration, idle time, and zone of use feed the invoice, and the trip log is tamper-evident so disputes are settled from the record.
Can the platform integrate with your existing booking and payment systems?
Yes. APIs let your reservation and payment systems drive the platform, with bookings issuing and revoking keys and usage closing out into your invoicing. Keyless access and metering are built to integrate with third-party booking platforms.
Does the box work across different car makes?
Yes. Integration over standard CAN and OBD-II is validated against each vehicle network in your fleet, so lock, immobiliser, ignition, and odometer behave correctly across mixed makes and models.
Ready to Build Your Car-Sharing Platform?
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