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This is our second post on Collision Response following on from our Introduction.

Trusting your smartphone to help detect and react to a road traffic collision might seem like a far fetched idea, particularly if you are used to thinking that special purpose vehicle hardware and sensors are the only way this can be done.

So today we’re publishing a Frequently Asked Questions on Collision Response to help address some of the most common questions we have encountered. It’s split into three main categories: Overall Functionality, Testing and Safeguards, and Usage Requirements.

Thanks go to our partners at Zendrive have reviewed and provided feedback on this FAQ, and also have their own really helpful resources on their website and blog.

Get in touch with one of our experts at if you’d like to know more about the system, and to request a demonstration.

Overall Functionality

How does collision detection work?

During a Trip, data from the motion sensors including the accelerometer (change of speed sensor), gyroscope (orientation sensor) and location services (location sensor and speed/heading estimator) are all continuously monitored and analysed in real time. Zendrive uses state of the art signal processing to detect the signature of a collision, which is characterised by large acceleration over a short window of time. The sensors are monitored at 100 Hz (one hundred times a second) which is how collisions, whose impact might be over in less than a second, can be reliably detected.

What information is contained in the collision alert?

Your location, user identity, and an alert flag. This information lets your location be shown on a map, and is needed to alert your monitoring team to know who to contact. In the future we intend to send the most recent trip information in addition to the collision location.

Who will the collision alert be sent to?

It will be sent to a monitoring platform (a dedicated server) and then immediately forwarded onto your monitoring team via SMS, email, and audio-visual notifications on a web application.

Who will respond to the collision alert?

Your monitoring team.

Will collision detection work if I am using my phone at the time of the collision, for instance if I am a passenger?

Yes. Collision Detection works regardless of the state of the phone or its orientation (in your hand, in your pocket, in a cup holder, in a mount).

Does Collision Response work if I am travelling at low velocity (under 20 mph) and another vehicle collides with me?

Collision detection is designed to work for vehicles traveling over 20 mph. If you are going slower than this and someone else collides with you, the Zendrive SDK will not detect it as a collision. The Zendrive SDK is also unable to detect when someone else collides with you, even if that person is moving at more than 20 mph at the time of the impact.

Does Collision Response work for motorcyclists?

Motorcycle trips will be detected. However as Zendrive collision detection has been optimised and calibrated for car collisions, you should assume that motorcycle collisions will not be detected.

Does Collision Response work for cyclists and pedestrians?

No. The SDK will not detect a car hitting you while you are on a bike or walking because it will only detect when you collide with someone else while you are moving at more than 20 mph. The SDK will most likely not even be active while you are walking or riding a bike because it is only designed to detect motor vehicle trips.

Will the local emergency services, law enforcement, or roadside assistance be automatically notified?

No. Our focus is on providing an automated, purpose built, private Emergency Response system to supplement what may be available as through public systems

If I brake suddenly, will this create a Collision Alert?

No. The Zendrive SDK can distinguish ‘harsh braking’ from a collision.

If I drop my phone will a collision alert be sent? Will there be lots of ‘false positives’ (false alarms)?

No. ‘Drive Mode’ needs to be active for Collision Detection to be active. In addition when Drive Mode is active, Collision Detection can distinguish the difference between a phone drop and a collision.

Testing and Safeguards

How has it been tested and calibrated?

Zendrive has tested and validated the reliability of their Software Development Kit (SDK) in crash test facility at BMW (one of Zendrive’s investors). These crash tests have allowed Zendrive to refine and improve the collision detection algorithm.

The SDK has been calibrated to detect serious collisions where the car is moving at more than 20 mph prior to the impact.

Zendrive’s SDK has also been installed in other safety apps, in turn installed on millions of phones. This means thousands of real collisions have been detected and analysed, allowing continual improvements to the SDK since it was launched in 2015.

It is a state-of-the-art, mature, stable and reliable SDK with a proven track record of accurate collision detection, among other features important for driving safety.

So Zendrive has tested and validated the trip detection and collision detection of their SDK. But how has the integration into Smart24 been tested and validated by Track24?

As part of Smart24 development, our engineering team has created a ‘test mode’ within the app, which allows us to manually start Drive Mode (a necessary condition for Collision Detection to be active). In this test mode we also have added the option to ‘raise a mock’ collision—using functionality provided by Zendrive—when Drive Mode is detected. This allows us to test the background automations and use of the network.

We have also physically validated that lesser acceleration scenarios, like a dropped phone, harsh braking and emergency stop from 60 kph, do not create false collision alerts, and we have validated Trip detection over hundreds of hours of drive time and hundreds of detected trips.

Our app also has ‘app crash reporting’ built in. This means that when the app crashes, (i.e. it stops working unexpectedly) we receive detailed information on the cause of the crash. This has enabled us to drive up the overall reliability and stability of Smart24.

In the interests of transparency, Track24 has not performed a crash test, like those that Zendrive have performed in the BMW test lab.

If Collision Response is an ‘autonomous system’ then what are the safeguards in place to make sure it is working properly?

During a drive (using caution), you can check that Drive Mode is active via a ‘Drive in Progress’ banner that appears on the Smart24 home screen. This banner disappears after the end of Drive Mode.

When there is no available network connection (or if you have you have run out of data in your plan) then an orange banner appears at the Smart24 homescreen. The absence of the orange banner means that Smart24 has active access to mobile data.

You can check that the alerting system works via our Emergency button, by performing an Emergency drill in coordination with your monitoring team.

Background Location access is such a fundamental part Smart24, that if your switch off Location Services, you will see a ‘blocking’ alert on the Smart24 home screen, directing you back to Smart24 settings to switch on Location Services.

What happens if I accidentally override or cancel the Collision Alert?

In this instance, we recommend that you use the Emergency button on Smart24 as a ‘fallback’. This will alert your monitoring team in the same manner as a collision alert.

Do I need to remember to launch the app before every trip I take? Like putting on a seatbelt?

No. On Android phones, Smart24 stays running ‘in the background’ at all times once you have launched it. On iPhones, Smart24 wakes if you move significantly, so it will be running ‘in the background’ even if you have ‘force closed’ it (by swiping the app upwards from the app switcher). Drive Mode is automatically detected when Smart24 is running.

Usage Requirements

What are all the necessary conditions for collision detection and alerting to work?

Firstly, the app and phone will need access to location services at all times.

Secondly, you will need a mobile data plan, and active access to mobile data during the trip and at the time of the collision detection in order to send a real time collision alert.

Collision Alerting won’t work in very remote regions with no mobile network. Although the collision will be detected because (as it doesn’t depend on network access), the data will not be sent to your monitoring team in real time.

If Drive Mode needs to be active for Collision Detection to be active, then how is Drive Mode detected and how reliable is it?

While you are stationary, the Zendrive SDK efficiently monitors your location and speed while your app is ‘in the background’. When it detects your speed being greater than about 7 mph for more 50 to 100m, Drive Mode is activated. i.e. Detection of a sustained period of motion in time and space is required for Drive Mode to be activated. When your phone comes to rest for a sustained period of time again, Drive Mode automatically ends, switching off Collision Detection.

You can verify when Drive Mode is active by opening Smart24: you will see a banner on the home screen with ‘Drive in Progress’. As always, caution should be used when looking at your phone screen while actually driving.

Detection of a trip might be delayed if you do not have an active mobile network connection, for instance if you are in a tunnel or underground. This is because a mobile network connection is typically required to achieve high location accuracy required by Zendrive.

Occasionally Drive Mode is activated when you have a less accurate location or have a weak mobile network connection. We currently remove trips that are less than 60m in length from the Trip Details page.

What happens if there is no network coverage at the time of a collision?

This is important. If there is no network connection at the time of a collision then the Collision Alert will not be sent: the automated alert relies on access to mobile data. This means that the Collision Alert feature is only appropriate for regions of the world where there is mobile network coverage, typically cities and motorways. The information about the trip and collision is still ‘buffered’ and stored on the phone, and would be sent when the network is available again.

How much battery power will Collision Response use?

Zendrive Trip detection, Trip monitoring and Collision Detection have each been highly optimised by Zendrive’s team of expert iOS and Android engineers to use as little battery power as possible on both operating systems. There will be slightly increased battery consumption during Drive Mode only, when Zendrive monitors and analyses sensor outputs more frequently.

In the near future we will provide quantitative benchmarks on the increased battery consumption during Drive Mode. Depending on your phone, the consumption is approximately in the range 0.5-1% per hour of driving.

How much mobile data will Collision Response use?

The only feature that is ‘real time’, and therefore requires access to mobile data, is the Collision Alert, which is a small packet of data. So overall, the additional mobile data footprint is minimal. There may be some indirect increase in mobile data consumption at the phone’s ‘system level’ as the phone makes use of location services during Drive Mode.

In the near future we will provide quantitative benchmarks. At this time we recommend to allow an additional 1 to 10 MB per day of active driving, depending on the amount of time you drive while using our Collision Response feature.