Driving assistant by DanAIWith you on every journey
Keep a safe
distance from
the car ahead.
Mount your phone on the windshield and Vững Lái uses the rear camera and on-device AI to remind you to keep a safe distance from the car ahead, based on your GPS speed and current Vietnamese regulations. The app is in Vietnamese for now; English menus and voice arrive with the next update.
- Free
- No ads
- No account
- For Android
Simulation
It watches the road, measures the gap, and speaks up on time.
Vững Lái spots the car ahead in your lane, estimates the distance and compares it with the minimum for your GPS speed. At 62 km/h, Circular 38/2024 requires at least 55 m.
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Safe gap
A thin green frame. Just focus on driving. -
Gap closing in
The frame turns amber as the gap shrinks towards the minimum. -
Too close
A red frame, with a tone, vibration and a spoken voice alert.
Features
What it does
One phone on the windshield, nine jobs quietly done for you on the road.
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Safe distance reminders
Spots the car ahead in your lane, estimates the distance and compares it with the minimum for your current GPS speed. Follows Vietnam’s Circular 38/2024/TT-BGTVT by default; you can switch to the 2-second rule or a table of your own.
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Forward-collision warning
Alerts you with a tone, vibration and a spoken voice alert when the gap closes fast.
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Lane-departure warning
Speaks up when the car starts crossing the line or drifting out of its lane.
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Speed-limit signs
Recognises speed-limit signs and keeps them on screen so you can keep track.
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Floating window beside the map
Shrinks into a floating window (picture-in-picture) so it runs alongside Google Maps.
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Self-calibrating camera
A mounting assistant helps you set the phone at the right angle; the app fine-tunes its calibration as you drive.
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Trip history
A summary of every trip, plus an optional GPS route log (off by default). All of it stays on the phone.
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Day, night and HUD
Day and night themes, plus a mirrored HUD mode for placing the phone below the windshield.
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Spoken voice alerts
In Vietnamese today, in English with the next app update. Pick a Standard, Friendly or Cheerful voice style, or write your own lines with Custom. No text-to-speech voice installed? You still get tones and vibration.
Circular 38/2024/TT-BGTVT
The default distance table
Under Vietnam’s Circular 38/2024/TT-BGTVT, on a dry road the minimum safe distance to the vehicle ahead is:
In rain or fog, on slippery roads, on mountain passes and steep slopes, or whenever visibility is limited, keep a larger gap than the table shows.
Private by design
Your drive stays yours.
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Processed on the phone
Camera images are analysed in the phone’s memory and never sent to any server.
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No account, no ads
No sign-in, no advertising or analytics SDKs, no tracking.
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Your data is yours
Settings and trip history live only on the phone. Clear the app’s data or uninstall it, and everything is gone.
Get started
Up and running in 3 steps
Do all the setup while parked. Once you’re moving, all you do is drive.
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Mount the phone
Landscape, high and near the middle of the windshield, with the rear camera looking straight down the road. The mounting assistant checks the position and angle for you.
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Open the app
Grant Camera and Location access and pick a voice before you set off. Need the map? Switch to Google Maps and Vững Lái shrinks into a floating window.
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Drive
Keep your eyes on the road. Vững Lái calibrates itself as you go and alerts you with a tone, vibration and voice when you get too close.
FAQ
Frequently asked questions
Mounting, calibration, permissions, voices and a hot phone: it’s all on the support page.
Read the full guideWhere should I mount the phone?
High and near the middle of the windshield: below or beside the rear-view mirror mount, offset towards the passenger side, clear of your line of sight and within the area the wipers reach. Mount the phone in landscape, and make sure the holder does not cover the rear camera lens.
Can I use it alongside Google Maps?
Yes. When you switch to Google Maps, Vững Lái shrinks into a floating window (picture-in-picture) and keeps warning you.
Why does the app need Camera and Location permissions?
The camera watches the road ahead; images are processed right on the phone, never stored and never sent anywhere. Location is used only while the app is open, to read your speed from GPS and pick the matching safe distance.
How do I change the distance rule?
By default the app uses the table from Vietnam’s Circular 38/2024/TT-BGTVT. In Settings you can switch to a time-based rule (for example the 2-second rule) or set up a table of your own.
Vững Lái is an assistance tool only. It is not a certified measuring device, it does not control the car, and its estimates can be wrong. The driver is always responsible for watching the road, keeping a safe distance and obeying traffic law. Set the app up before you set off, and don’t handle your phone while the car is moving.