Varia vs Fly6

A cyclist usually knows when someone is too close behind unless they are wearing something that prevents them from hearing properly. Also, if there is something behind you what can or should you do about it? Move out of the way? You have as much right to use the road as the vehicle behind you.

Perhaps what would be useful is a radar system linked to a camera so that you can capture near misses, aggressive driving, and worse. However, in the UK the police want footage from 2 minutes before and 2 minutes after an incident, so the radar system would need to have some way of predicting the future.

I use and like both. One does not compete with the other. If I had to choose it would be the radar. It gives you real time information that you can act on. The radar works very well and after using it for a while you get pretty good at knowing what is going on and what to do. My view is just because you have the same right to a part of the road, the reality is the car or truck wins every time if they make a mistake. You can be right and also be dead. My philosophy is to stay as far away as I can. I also use the varia vision and they work great together. A little vibration tells you a car is coming and you can then glance and see, how many, how far back, etc. fly6 is a great light and it works, but it is more of an insurance policy if something happens to have some recourse. Much brighter light than the radar. Radar is not a great tail light.

A cyclist usually knows when someone is too close behind unless they are wearing something that prevents them from hearing properly. Also, if there is something behind you what can or should you do about it? Move out of the way? You have as much right to use the road as the vehicle behind you.

I have to disagree with you on a few points ...

• A cyclist usually knows when someone is too close behind: That's not always true ... especially when you're riding on a windy day. Plus, I like to know that there is a car behind me long before I can hear it.
  
• What can or should you do about it: Be prepared for the vehicle to pass you. Move a bit closer to the side if necessary. Call out "Car Back" so others riding with you know there is a car behind.
  
• You have as much right to use the road: Very true ... but many drivers don't understand that concept. Plus, a driver is protected by several thousand pounds of metal ... a cyclist is not. Better to ride defensively and be safe than to trust drivers to care about your welfare.
  

david

My vote would be for both if possible since they serve two very different purposes. If that's not possible the Varia would be my pick. Frequently it will detect cars and alert me to them well before I can hear it. Sometimes it even finds them before the furthest back person in group ride hears it can lets us know. The display on my Edge 520 is also helpful since it shows how many cars are coming and how fast they are approaching. If one is coming up really fast I'll know to look and be prepared to take evasive action if they don't move over. The other nice thing the Varia does is that more of the light bar is lit up as the car gets closer to make you more visible to hopefully improve the chances of the driver seeing you.

The only caveat is if you are mostly riding on city streets with heavy traffic the Varia won't be as useful since it will be going off all the time. On suburban and country roads it is much more useful, especially if you are on a very low traffic road and might zone out a bit while riding since the alert from the Varia will get your attention.