A driver's log for the people who actually pay attention. Live speed, G-force,
hard-accel and hard-brake events, auto-detected 0–100 times — captured per session,
per vehicle, on the road or on a closed course. No social feed, no gimmicks.
Some drives you plan — a hill climb, a stretch of canyon, a destination you've timed before.
Others just happen. LeftLane handles all three, with the right HUD for each.
MODE / 01
Free DriveYou start. You stop.
Hit Start, drive, hit Stop. Live speed, G-force, max, average, distance, hard-accel and hard-brake counts — measured for the duration of the session. Weather snapshot at start, posted speed limit overlaid on the HUD.
Manual start / stop
Auto-pause when stationary > 5s
0–100 km/h auto-detect (sub-second)
Tag at session end
MODE / 02
ChallengeDestination. Finish line.
Pick a destination on the map. We route it, compute a perpendicular finish line, and time you from start to crossing. Live ETA, ±s vs your personal best, next maneuver — all on a HUD built for sideways glances.
Tap-to-pick or search destination
Routed distance & live ETA
±s vs personal best, per destination
Sub-sample finish-line detection
MODE / 03
Hands-FreePhone in mount. Drive.
Sustained hard acceleration for 5 seconds and the app starts recording on its own. No tap, no fumbling. Stops when you say so. The HUD turns itself on when you actually drive.
Accelerometer-triggered start
Background tracking optional
Auto Do-Not-Disturb during session
Voice cues for state changes
02 Captured per session
Telemetry, not vibes.
10 Hz GPS, 100 Hz IMU, barometric altitude when the device has one — fused on-device through
an extended Kalman filter into a smooth 30 Hz stream. Per-vehicle mount calibration so the
G-force numbers actually mean something. Weather snapshot at start, posted speed limit
overlaid on the HUD.
Max speed · session
228km/h
Speed-limit overlay · OSM + 12-country fallback
0 → 100 km/h · auto-detect
4.81s
Personal best · BMW M5
Max G
1.34g
Vehicle-frame · post-calibration
Distance · session
47.2km
Moving time vs total elapsed
Elevation gain · barometer
412m
Max alt 684 m · GPS fallback
Moving time
23:54
Auto-pause < 1 km/h
Session tags
canyon-runbackroadsunday-drivesolodry
Free-form. Filterable in History.
Mount calibration · M5
94% conf
Pitch −2.4° · Roll +0.7° · Yaw +1.1°
Hard acceleration · > 0.4g for ≥ 0.5s
3events · 4.2s total
00:04:120.62g
00:11:380.48g
00:19:020.54g
Hard braking · < −0.5g for ≥ 0.5s
1event · 0.9s total
00:14:57−0.78g
03 The garage
One key, many keys.
Every session belongs to a vehicle. Two cars, three bikes, one daily and a weekend toy —
LeftLane keeps the records separate so the personal-best on the M5 isn't getting padded
by the GR Yaris.
Hit Share during a drive. We mint a short token and push your live position to a public
URL. They open the link — phone, browser, whatever — and watch the trail draw itself in
real time. No app install on their end.
▸QR + short link in the bottom sheet
▸Trail polyline + live puck · 5s refresh
▸Viewer count visible to the driver
▸Auto-expire on stop or after 1 hour
● LIVE · SESSION 04214watching
● 184 KM/H · NE14.2 KM · 11:27
// SHARE LINK
leftlane.run/live/k7q9m
47:12until expiry
05 Go live on camera
Put them in the passenger seat.
A live share streams your line on the map. Add a camera and they ride along. Broadcast
straight from the phone — front or rear, with mic — or bring a real rig: a GoPro, Insta360,
or DJI streams in over RTMP. The feed lands on the same public page, a few seconds behind
real time, video beside the trail. Still no app install for whoever's watching.
▸This phone · pick front or rear + mic, tap Go Live
▸Any RTMP action cam · GoPro · Insta360 · DJI
▸We hand you the ingest URL, stream key + QR
▸Shows on the live page, right beside the trail
▸Give the camera its own data — telemetry keeps its bandwidth
RECGOPRO HERO
00:14:27
This phoneExternal cam
// POINT YOUR ACTION CAMERA AT THIS ADDRESS — GOPRO · DJI · INSTA360
// Camera URL (RTMP)rtmps://live.leftlane.run/k7q9m
// Stream keysk_4f2a··········COPY
06 Live chat
They talk. You drive.
Flip chat on when you start a session and your live link turns two-way. Anyone watching
picks a nickname — no account, no install — and messages you while you run. You're driving,
so it stays one-way: their lines land on your phone, you read at a glance, eyes up. Turn
Public chat on and the link becomes one room everyone sees;
leave it off and each viewer gets a private line to you — nobody else sees it.
▸Host switches chat on when starting the session
▸Visitors pick a nickname · no account, no install
▸One-way · the driver reads, eyes on the road
▸Public chat ON · everyone sees the same room
▸Public chat OFF · each viewer is private to the driver
// CHATPUBLIC
tiresmoke_92send it through the tunnel 🔥
momplease slow down
apex_andywhat did that 0–100 run??
you4.8 — receipts on the share-card 😎
// Try it — this preview stays in your browser, nothing's sent.
07 Verified share-cards
Screenshots lie. Cards don't.
Every session can export as a single PNG with a signed payload baked in. The app
recognizes its own — so when a friend posts a 3.4-second 0–100, you'll know whether
the number is real or whether they opened it in Photoshop.
▸HMAC-signed payload in PNG tEXt chunks
▸QR code baked in · screenshots still resolve
▸Verify panel: drop in any card · ✓ or ✗ in 200 ms
▸Short public link · leftlane.run/s/<slug>
REC
// 0421
C H A L L E N G E
@JOHNDOE_RS
Vehicle · 2021
BMW M5
Max speed
228km/h
0 — 100
4.81s
Distance
47.2km
Max G
1.34
08 Driver honors
Earn your stripes. Bronze to platinum.
11 honors in the launch catalog, across foundation, distance, endurance, streaks, smooth
driving, variety, and map engagement. Each one tiered where it makes sense, tracked
per vehicle where it matters. Re-evaluated after every session.
// DISTANCE
Long-hauler
Total kilometers logged on a single vehicle. Counted per car or bike.
100km
1kkm
5kkm
10kkm
// STREAKS
Daily driver
Consecutive days with at least one recorded session. Skip a day, the streak resets.
3day
7day
14day
30day
// VARIETY
Night owl
Sessions started between 22:00 and 04:00 local time. Different rules for different hours.
Tap a building and we reverse-geocode the OSM footprint, drop a colored pin, and
remember it. Speed limits read from OSM tags with country-default fallback for 12+
countries — so the limit pill on the HUD is right, even on backroads OSM hasn't
labelled yet.
OSM building geometryPolygon footprint, not just a dot. Name it. Color it. Yours.
Posted speed limitsLive on the HUD. ±3 km/h grace before over-limit pulses.
Country defaultsRS, DE, AT, HR, SI, BA, ME, MK, XK + fallback rules.
Road class & nameMotorway, residential, trunk — captured per fix.
● 184 KM/H · 142°3 marks visible
80posted · OSM
10 Built thoughtfully
Quiet things that matter.
Privacy that holds up on Android and iOS, sessions that don't drop when the tunnel does,
plate-blur that runs on the device, and a disclaimer you actually have to acknowledge.
License-plate blur
Garage and maintenance photos run through on-device ML Kit text recognition. Plates get Gaussian-blurred before the image ever leaves your phone.
Biometric lock
Face ID, Touch ID, or device passcode — required on app start and again to resume a session after the screen locks.
Per-launch disclaimer
A slide-to-accept liability screen at every launch. Logged server-side with version. Not a checkbox you can tap by accident.
Your data, exportable
Download sessions and profile as JSON or GPX. Delete your account and it's actually deleted. Personal heat map is opt-in.
Offline buffer
Every fix is written to SQLite first. Lose signal in a tunnel, the data doesn't go with it. Uploads when the network's back.
Battery, OEM-aware
Detects aggressive families — Xiaomi, OnePlus, OPPO, Samsung, Huawei, Vivo — and walks you through the exact toggle so the OS doesn't freeze your session.
Weather per session
Temperature, condition, and a 24h forecast pulled at session start so dry-run lap times don't get compared to a wet-track effort.
Home-screen widget
Android widget shows last-session stats — distance, top speed, 0–100 — straight on your launcher. Updates after every sync.
11 What's coming
Already on the map.
v1 ships with three recording modes, full telemetry with EKF fusion and mount calibration,
garage, segment racing, live share, driver honors, marked places, and verified share-cards.
The rest is queued.
v1.1
Personal wallpapers
Render a wallpaper from your own stats — top speed, distance, fastest 0–100, brand-pack typography. Five brand-pack designs already ship.
QUEUED
v1.1
Multi-lap mode
Track-day lap timing with a start/finish line you set. Sector splits, fastest lap, lap-over-lap delta. Infrastructure is in; needs UI.
IN BUILD
Soon
Email + Password
OAuth-only at launch (Google + Apple). Email sign-up is on deck if real demand surfaces.
QUEUED
Soon
OBD-II Bluetooth
Pair a dongle, read speed and RPM straight from the ECU. GPS becomes a backup, not the source.
RESEARCH
Soon
The Heat List
Username, vehicle, stats — global & regional leaderboards. The third top-bar slot is already reserved.
DESIGN
Later
CarPlay · Android Auto
Speed and session status on the in-dash display. Different surface, real effort.
RESERVED
Later
Apple Watch · Wear OS
Start/stop from the wrist. Haptic feedback on hard-accel events. Different from the in-app spectator "Watch" feature.
RESERVED
Later
Crash detection
Sustained negative G + sudden stop → ping an emergency contact. Needs a safety review before it ships.
VIN · WBSXX0C0XXM·M5
VIN · JYARN6E0XPA·R1M
