Honest question - How is it helpful to know a car is coming? On my commute to work I have a bike lane and 100s of cars pass me in their lane, knowing a car wouldn't be helpful, knowing a car was going to hit me also may not be helpful if I couldn't move over, exactly what is the benefit?

I have one of the Garmin varia radar lights and feel exactly the same about them.

> Where in the world do you live / where do you typically ride your bike? In what situations are you glad to have that radar?

UK; It's handy for knowing when on town or country roads without too much traffic; it can typically spot fast moving vehicles before you can hear or see them in mirrors (let alone if relying solely furtive glimpses over shoulder)

Tbh, nice as it is to be notified about approaching vehicles, what I really like is that the light flashes at proportionately faster rates in response to the speed of the approaching vehicles. The changing rate does a better job of attracting the attention of drivers than constant illumination, and is also a psychological hack that makes the driver think they are being watched [0] and consequently behave slightly better when they do pass.

Cumulatively the light/radar combination is a winner because it makes cycling more pleasant _and_ reduces the chances of getting hit by drivers.

[0] In some of the newer units they are being watched as well, as they have camera's in them - apparently unit is a bit chunky and video quality in low-light is ropey.

> I don't remember the last time I was surprised by a car approaching from behind.

With a headwind I often don’t hear cars behind me at all, so I can see the use case

Not op but I also have a varia and feel safer for it. Living in Switzerland, cycle a lot on public curvy roads in the alps. Often I don’t hear someone coming if I’m focusing on something else important - like traffic in the other direction - or I don’t realise there’s actually more than one car about to overtake which the Varia also shows. Generally turning your head around to check is a bit dodgy!

> I'm struggling to understand the need. I ride my bike every day but I don't remember the last time I was surprised by a car approaching from behind.

Not get rear-ended by a car? There's also model with a camera to collect evidence. I have the one without the camera, just the radar and a light.

> Where in the world do you live / where do you typically ride your bike? In what situations are you glad to have that radar?

Central and Eastern Europe. Whenever I share the roads with cars. Although I'm more relaxed on outdoor paths or gravel roads where I don't have to keep an eye on cars all the time.

For MTB you probably don't need it, but in road scenarios it's great.

Yeah you probably don't need it in slow moving urban traffic but I saw a video with some bike packers in Australia who used Varia. They were on rural roads shared with road trains.

Road trains a very big, move very fast and they don't stop for anyone on a bike. So knowing they are coming up on you from a distance gives you time to get off the road.

That's a very special usage case but I think any rural road with fast moving traffic would also benefit from the early warning even with just cars to contend with.

> Where in the world do you live

I’m in New Zealand. I ride in the road in town and out in the hills at the weekend.

The way I use it is to look down, see if a car is behind, then look behind before pulling out. I don’t bother looking back if there is a car close (the range must be around 100-150m I think?).

It also yells louder if the car is approaching fast. The integrated light changes how it flashes when it sees a car.

In group ride with talking etc, it’s helpful too as it usually doesn’t pick up bikes (unless the guy behind is an absolute unit) and the squawk of an approaching car is helpful for the group.

Electric cars and busses no longer sneak up on me, it’s great use of tech on a bike.

https://www.garmin.com/en-US/p/698001/

US. I ride shoulders on semi-rural highways. Sometimes there will be traffic in the opposing lane creating enough noise that I don't hear the vehicles coming from behind. With my Varia, I get warned well before they show up. It has even detected "hidden" vehicles that I couldn't visibly see -- like a small car trailing a truck.

Buses! The front of the bus arrives much earlier than the engine up the back where most of the noise comes from

Are modified ebikes popular where you live yet? They can be very fast, very quiet and will do a lot of damage if you collide with one.

Anywhere that has cyclists sharing the road with cars.

Better but circumstance dependent. Its for rural roads, and less busy roads. Not urban traffic

You have so many negatives in your statement I had to read it 3 times as a native English speaker to realize it doesn't make sense. We can make cycling safer in multiple dimensions simultaneously: 1. we learn from the Dutch about infrastructure and integrating cycling into the transportation fabric (slow and expensive), 2. the Dutch start wearing helmets (fast and cheap).

There's so much the world can learn from the dutch when it comes to traffic