What the app does (high level)
Runs on the user’s smartphone (Android + iOS).
Continuously (but efficiently) monitors sensors while the phone detects driving (activity recognition).
If a likely crash is detected it: (a) opens an on-screen alert to let the user cancel, (b) if no cancel, automatically sends location + crash metadata to an emergency dispatch service and to the user’s emergency contacts, and (c) calls local emergency services / a partnered call center that notifies police/ambulance.
Optionally collects additional context (photos, video clip, sensor logs) to help responders and insurers.
This is how OnStar, Apple Crash Detection and several apps work.
onstar.com
+2
Apple Support
+2
2) How crash detection works (practical details)
Inputs you can use
Smartphone accelerometer & gyroscope (sudden high g-forces, rotation).
GPS speed + sudden deceleration.
Microphone (loud impact sound) — optional, privacy-sensitive.
Activity recognition / vehicle presence (to ignore walking/running).
Car data via Bluetooth OBD-II / CAN adapter for brake/fault signals (if the user has adapter).
Research + prototypes show smartphone sensors can detect accidents reliably when combined intelligently.
cs.wm.edu
+1
Detection logic (two layers)
ML-based classifier (reduces false positives): train a lightweight model that uses accelerometer/gyro/GPS + context (time of day, phone orientation, recent speed) to distinguish crashes vs. potholes / hard braking / dropping phone. Use supervised data from crash logs + synthetic data from simulator/bench tests. Patents and papers exist for these hybrid approaches.
Google Patents
+1
User confirmation flow
Immediately show an alert: “We detected a possible crash — call emergency services?” with a big Cancel button and a visible timeout . If user cancels, stop. If not, escalate automatically. Apple/Noonlight show similar flows.
The Verge
+1
3) System architecture & data flow
Device layer (phone): sensor collection, local inference, UI for alerts.
Backend / Cloud: receive verified crash reports, store incident logs, provide API for responder integrations, notify emergency contacts.
Dispatch / Call center (critical): partner with a 24/7 monitoring center (or build your own). The monitoring center verifies incidents and calls local emergency services / police / ambulance with location & incident severity. Many services do this rather than calling 911 directly from the app to avoid false alarms and to handle language/triage.
OtoZen
+1
Third-party integrations: SMS/voice gateways, local 112/911 APIs where available, ambulance dispatch APIs (if region supports), insurance portals, vehicle telematics (optional).
Data sent on escalation
GPS coordinates (lat/long), timestamp, severity estimate, vehicle heading/speed, sensor snippet (accelerometer/gyro), optionally photo/video/video-snapshot, user profile (name / medical info / emergency contacts). Keep payload small to deliver fast.
4) Legal, privacy & compliance (must-haves)
User consent for continuous sensor monitoring and for sharing location/health info. Provide clear in-app onboarding.
GDPR / local privacy laws: store minimal data, provide deletion and export options. Encrypt data in transit and at rest.
Medical info opt-in: only share allergies / meds if user explicitly enters it.
False alarms & liability: include terms that define what the app does; partner with official dispatchers to reduce unnecessary 1-9-1 calls.
Local emergency call rules: in many countries only citizens can directly call emergency numbers from apps; best practice is to send data to a certified dispatch center that then calls local services. OnStar/other operators use certified monitoring centers.
onstar.com
+1
5) MVP roadmap (practical step-by-step)
Phase 0 — Research & prototyping
Collect sample sensor data: normal driving, braking events, potholes, collisions (simulate safely), using phones mounted in cars. Use public datasets/papers for initial models.
cs.wm.edu
+1
Phase 1 — Minimal viable app
Platforms: Android first (more sensor access), then iOS.
Features: background activity recognition, crash-detection rule-based engine, local alert UI with cancel; on-confirm send SMS + GPS to emergency contact + simple cloud log.
No direct police integration yet — use SMS & phone calls to emergency contacts.
Phase 2 — Monitoring center & integrations
Partner with a 24/7 dispatch/monitoring service (or build) that accepts incident webhooks, calls local EMS/police, and tracks response. Add voice channel so the dispatcher can call the user automatically.
OtoZen
Phase 3 — Advanced
ML model to reduce false positives, OBD-II / CAN adapter integration (brake faults, airbag deployment), video/photo capture on event, insurer partnerships.
Multi-user/fleet features for commercial users.
6) Tech stack & components
Mobile: Kotlin (Android) / Swift (iOS) or React Native / Flutter if you want cross-platform but native gives best sensor access.
Local processing: small rule engine + TensorFlow Lite or Core ML for on-device ML.
Backend: Node.js / Python (FastAPI) + PostgreSQL; or serverless (AWS Lambda + DynamoDB) for rapid scaling.
Real-time: Webhooks + push notifications (Firebase, APNs).
Dispatch integration: REST API + SIP / telephony (Twilio, Plivo) to call emergency contacts or call centers.
Security: TLS, JWT for auth, encrypted PII storage.
7) False positives — how to minimize them
Require multiple signals: a high-G event and sudden speed loss and activity=driving.
Use context: phone mounted vs in pocket (orientation), road type (GPS speed), time-of-day heuristics.
Provide quick cancel UX and a reversible escalation (dispatcher calls before sending ambulance if appropriate).
Improve with ML retraining from labelled user events.
8) UX and user flows (must be simple)
Onboarding: request permissions, set emergency contacts, add medical info, show how detection works.
During drive: minimal battery usage, low-notification background mode.
Crash alert: large cancel button, 20–30 second countdown, auto-call if not canceled.
After event: show incident summary, allow editing, share with insurer/family.
9) Partnerships & go-to-market
Monitoring centers: contract with a certified 24/7 monitoring provider (many exist globally).
OtoZen
OEMs / telematics providers: later integrate with manufacturers or OBD-II dongles for richer data. OnStar and others show the value of embedded vehicle sensors.
onstar.com
Insurance companies: offer the app as a safety feature for discounts.
Ambulance/Police APIs: where available, integrate directly for automated dispatch.
10) Monetization options
Freemium: basic crash detection & emergency contacts free; premium adds monitoring center + dispatch, verified incident reports, video uploads, family sharing. (Noonlight and others use a subscription model.)
Teen Vogue
B2B: sell fleet/enterprise plans to logistics companies.
Partnerships with insurers for reduced premiums or co-marketing.
11) Benefits / positives (why this helps)
Faster emergency response → fewer deaths and better outcomes.
Works in older cars without built-in telematics (smartphone-based).
Provides evidence (location, sensor logs, video) for rescue and insurance claims.
Peace of mind for family members when loved ones drive alone. Real-world services (OnStar, Apple Crash Detection, third-party apps) have demonstrated this value.
onstar.com
+2
Apple Support
+2
12) Challenges & risks
False alarms → unnecessary dispatch costs and user fatigue. Mitigate with multi-signal detection, cancel UX and monitored escalation.
Privacy concerns over continuous monitoring — minimize retention and be transparent.
Regional emergency call rules and integration complexity — partner with local dispatch centers.
Liability — legal review & terms of service required.
13) Example minimal feature list to start building today
Background driving detection (activity recognition).
Rule-based crash detection (accelerometer + GPS speed drop).
In-app cancel alert with countdown.
Automatic SMS / location to emergency contacts + cloud incident log.
Admin dashboard (simple) listing incidents and status.
Once this is stable, add a paid 24/7 monitoring partner to make real dispatches.
14) Useful references & real-world examples
OnStar Automatic Crash Response (embedded telematics model).
onstar.com
Apple Crash Detection documentation (device-based detection and auto emergency call).
Apple Support
Academic papers / WreckWatch on smartphone crash detection algorithms.
cs.wm.edu
+1
Noonlight / other safety apps that implemented crash-to-911 behavior and subscription models.
Teen Vogue
Quick next steps you can take right now
Prototype: build an Android prototype that logs accelerometer/gyro/GPS and triggers an in-app alert on threshold breach. (Use a mounted phone during controlled hard braking tests.)
Collect labeled data: gather sample logs for normal driving, hard braking, potholes, and simulated impacts. This is the most valuable asset for tuning.
Contact monitoring centers: talk to 1–2 24/7 monitoring services for integration & pricing.
Legal review & privacy plan: draft consent screens and data retention policies.
If you want, I can:
produce a detailed MVP spec (API endpoints, DB schema, screen mockups),
write sample Android code that reads accelerometer/GPS and triggers the cancelable alert,