An extra eye on the road: BMW’s collision warning system alerts you to hazards ahead

How the BMW collision warning will work on the road
How the BMW collision warning will work on the road

BMW have developed a front collision warning system that’s due to debut on a production bike “in the near future”. No prizes for guessing that’s the incoming BMW R1300GS, then.

The system is designed to prevent riders running into the back of vehicles ahead – if, for example, the rider is distracted and hasn’t noticed traffic in front slowing down. It relies on a forwards-facing radar sensor, just like the one BMW already uses for Active Cruise Control (which adjusts the bike’s speed to maintain a safe distance in traffic) on the BMW R1250RT.

The front collision warning aims to offer additional safety even when ACC isn’t switched on, first by alerting the rider, and slowing the bike if necessary.

BMW collision warning dash alert

So long as you’re in a riding mode with ABS fully active (eg Road, Rain or Dynamic, but not Enduro Pro) and are riding between 30 and 160kph (roughly 20 to 100mph), the Front Collision Warning (FCW) system will be active. The radar reads the road ahead, monitoring the distance to vehicles in front and calculating your closing speed.

If the numbers suggest you’re gaining on a vehicle fast enough to cause a problem, FCW starts by displaying a small red car icon as a pre-warning on the dash. But because the system is designed to alert a rider whose concentration has slipped, it also delivers a physical “haptic pulse”.

This uses the ABS pump to gently pulse the brakes twice. The aim isn’t to slow the bike, but to create a “ba-dum” feel through the bike that draws the rider’s attention back to the road.

BMW collision warning alert message

If that doesn’t work, FCW follows up with a more overt warning – a large red car icon fills the display – followed by the system gently applying the brakes.

BMW stress that the bike will never perform an emergency stop, and deceleration is limited to a fairly mild 4.4 m/s2 (less than 0.5G). The intention is just to slow the bike enough to buy more reaction time – it’s up to the rider to decide between braking more strongly or taking avoiding action. It’s not a crash avoidance system: the bike won’t stop an accident on its own. That’s still your job…

To ensure riders don’t get bothered by false warnings, the system varies its warning threshold using something BMW calls a “rider attention estimator”. In short, this monitors your inputs (ie it knows whether you’re fiddling with menus, or whether you’re using the throttle and gears actively) and uses this as a guide to whether you’re paying attention or not.

BMW front radar

If it thinks you could be distracted, it’ll give alerts earlier than if it believes you’re focused on riding. BMW say the setup is so good that test riders have returned saying the FCW system was faulty as it never showed a false alert.

BMW add that you can switch FCW off – and it won’t turn itself back on the next time you come to ride the bike either.

BMW’s collision warning system in detail

Radar love: BMW’s front collision warning system starts with a radar sensor scanning the road ahead, monitoring your distance to traffic and relative closing speeds. If it thinks you’re at risk of running into the back of another vehicle, a two-stage warning system kicks in.

Good vibrations: When a hazard is spotted the dash displays a pre-warning icon, followed by two gentle pulses of the brakes. Nothing strong enough to slow or unsettle the bike; just a physical alert designed to draw your attention to the road ahead.

Ready to slow: If there’s no response to the pre-warnings, the system can gently apply the brakes to buy more time. If the rider chooses to squeeze the brakes harder then there’s already pressure in the system. If the rider opens the throttle, brakes are released.

BMW's front radar unit as fitted to an R1250RT

Don’t like it? Don’t use it: BMW are clear to make out that the system isn’t compulsory. If you don’t want the alerts, you can switch the whole thing off and the system will remain off the next time you come to start the bike. If you like the system but don’t want the haptic alerts, you can switch those off separately too.

Paying attention? To avoid false warnings, the kit uses a ‘rider attention estimator’. It monitors your inputs to the bike – whether you’re fiddling with modes and menus, doing nothing, or working the throttle and gears – and alters its warning threshold accordingly.