Rear radar - any good?

[Mike_P]

My Varia shows a solid green line when the road behind is clear. When there is a vehicle behind me travelling at the same speed then a car icon, or icons if more than one car, will show.

Apologies was referring to the Elemnt Blot.

 

[Sea of vapours]

I'm not being negative or down playing how useful some find the radars, just wondering about effectiveness against bad drivers.

Any additional information may help you to do something in positioning or behavioural terms which will help you to mitigate the risk from a bad driver. They are, however, perhaps most useful on quiet / not busy roads, where you will be alerted to the one car every few minutes; not so much on a busy road where a car is passing every few seconds and you're therefore constantly on alert for bad drivers. Personally, the combination of a radar to alert me to the presence of an approaching vehicle and a mirror to check what it is, is very powerful in allowing appropriate road positioning and behaviour.

 

[Mike_P]

I use mine on a number of busy roads and once it has bleeped for the first approaching car it is then slient until it goes clear. You consequently know then when its worth looking back to make the approaching right turn.

 

[Ajax Bay]

Isn't it always "worth looking back" before signalling to manoeuvre to the centre of the road before a right turn. How does the radar info inform your timing? Do you look back earlier or later if you know there's a vehicle right behind?

 

[HLaB]

My point is though even if the radar alerts you to a vehicle(s) behind I'm not entirely sure how that helps if said vehicles are going to close pass etc anyway. Example you are riding along a road with traffic fairly frequently overtaking. So, I assume as vehicles approach you get an alert which tells you they are approaching etc but what then? Do you then check over shoulder for every vehicle, surely that's not feasible on a busy road. Do you alter line every time?

Being aware they are there is something I find helps a lot (no or less WTF moments as I'm expecting them). Similarly if there's multiple vehicles you don't have repeated WTF moments and you know when its clear and you can do a single shoulder check before you manoeuvre. Situational awareness. Relatedly its a good benefit (to say the least) being able to look forward 99% of the time, especially with the state of our roads and the pull out from dodgy drivers or to avoid other common hazards. I only move position though 99% of the time when I want to make a positive manouvre. My head unit and a lot of others are colour coded and large enough that you can judge their distance and speed, which heightens the benefits/ confidence/ situational awareness. If it goes red you know they are going too fast, but if it changes to orange they'll have saw you; they are far back or sitting patiently behind etc. I would have probably been in the 'why' camp until I got one and now I feel naked without a radar. You've really got to try one before you realise why they are good though (actually IMO they are better than good) .

 

[PaulSB]

@HLaB on the nail. 👍

This ^^^

 

[PaulSB]

Isn't it always "worth looking back" before signalling to manoeuvre to the centre of the road before a right turn. How does the radar info inform your timing? Do you look back earlier or later if you know there's a vehicle right behind?

I think what @Mike_P means is that if the radar is clearly indicating there's a vehicle approaching depending on the road situation there may be no point in shoulder checking until the vehicle has passed. He waits until the radar is giving the all clear. This varies depending on road, traffic etc. just as it does without radar.

Can we agree many decisions on manoeuvring are instinctive? I won't state at "xxx" hundred yards I begin to check. This would be untrue, I instinctively know what my behaviour should be according to the current situation. I feel each radar user will develop their own strategy for using the device with us all ending up with the same result. The following applies to a manoeuvre whether I'm using radar or not.

I know when I'm going to turn, and depending on road conditions I will decide when to check. The radar informs me if there's a vehicle following and a good indication of where and how many. For a simple turn, plenty of visibility, low traffic as I approach the turn I wait for vehicle(s) to pass, the radar indicates this, before I shoulder check. Once I've checked I move into the correct road position.

With more difficult situations I already know there is traffic approaching, how much and how quickly. If it's busy I will begin to shoulder check much earlier as the information I have tells me I need to be assessing the situation ASAP, looking for the traffic gap, the friendly driver who will sit back while I change my road position and turn. We all do this.......I hope.

The benefit of radar is, particularly in busy or tricky conditions, one is better informed, earlier nothing more or less.

There is no device that can tell a road user when to manoeuvre but there are devices that aid our decisions. That is the definition of radar, an aid.

 

[Mike_P]

I think what @Mike_P means is that if the radar is clearly indicating there's a vehicle approaching depending on the road situation there may be no point in shoulder checking until the vehicle has passed. He waits until the radar is giving the all clear. This varies depending on road, traffic etc. just as it does without radar.

Yes there's no point looking back when the Varia is indicating a constant flow of approaching traffic.
For instance, theres a right turn on the A61 with a lengthy right turn lane so if there is a queue of passing traffic I slow and so far an apparent gap in approaching traffic has eventually been indicated by the Varia confirmed by looking back.

 

[Ajax Bay]

I think what @Mike_P means is that if the radar is clearly indicating there's a vehicle approaching depending on the road situation there may be no point in shoulder checking until the vehicle has passed. He waits until the radar is giving the all clear. This varies depending on road, traffic etc. just as it does without radar.

Fair. I guess the timing of signal before manoeuvre is driven by the time it'll take to reach the junction and this trumps waiting till there's no vehicle behind. As for "no point in shoulder checking till the vehicle has passed" I reckon, perhaps it's my wishful illusion, that the movement of a rider's deliberate look behind increases most drivers' focus on the obstruction ahead and deliberate passing (or not) with due care. Rear radar offers info on what's behind. Whether that's actionable info is moot. We've all been surprised by 'quiet' passes: info from rear radar reduces that surprise.
Mike's "turning off the A61" (right) sounds like a niche case.

 

[Binky]

Being aware they are there is something I find helps a lot (no or less WTF moments as I'm expecting them). Similarly if there's multiple vehicles you don't have repeated WTF moments and you know when its clear and you can do a single shoulder check before you manoeuvre. Situational awareness. Relatedly its a good benefit (to say the least) being able to look forward 99% of the time, especially with the state of our roads and the pull out from dodgy drivers or to avoid other common hazards. I only move position though 99% of the time when I want to make a positive manouvre. My head unit and a lot of others are colour coded and large enough that you can judge their distance and speed, which heightens the benefits/ confidence/ situational awareness. If it goes red you know they are going too fast, but if it changes to orange they'll have saw you; they are far back or sitting patiently behind etc. I would have probably been in the 'why' camp until I got one and now I feel naked without a radar. You've really got to try one before you realise why they are good though (actually IMO they are better than good) .

Yes I get all that and agree the advance warning is good to stop the sudden fright of a speeding car going past but my point is it doesn't do any more than a mirror as it won't help in a close pass situation, that is the cyclist is still as vunerable and exposed to danger. I've had instances on a road where cars have gone past me at 60mph+("quiet" A roads which are good to cycle but cars able to drive fast) so even if I see them approaching from behind you never know how they will pass you as they are upon you and past so quickly especially if it's an incline and I'm doing say 15mph max in comparison.

Again, I'm not trying to downplay or be negative about the radars, just wondering about effectiveness to keep me safe.

Anyway, it's club ride today so unless I bail due to forecast I know the ride leader is a recent advocate of rear radar so I'll also quiz him on it.

 

[geocycle]

Yes I get all that and agree the advance warning is good to stop the sudden fright of a speeding car going past but my point is it doesn't do any more than a mirror as it won't help in a close pass situation, that is the cyclist is still as vunerable and exposed to danger. I've had instances on a road where cars have gone past me at 60mph+("quiet" A roads which are good to cycle but cars able to drive fast) so even if I see them approaching from behind you never know how they will pass you as they are upon you and past so quickly especially if it's an incline and I'm doing say 15mph max in comparison.

Again, I'm not trying to downplay or be negative about the radars, just wondering about effectiveness to keep me safe.

Anyway, it's club ride today so unless I bail due to forecast I know the ride leader is a recent advocate of rear radar so I'll also quiz him on it.

There is overlap between the capabilities of the radar and a well placed mirror, but the radar is better in some situations. For example going down hill, you hear a noise behind but wind makes it hard to be sure, the road is rough and you want to pick a line between potholes, an orange flash from the head unit alerts you there is a vehicle and it’s safer to grit your teeth in a straight line through the potholes. Checking a mirror in those circumstances and processing the image means taking your eyes off the road.

I was a gadget sceptic but I’d not be without the radar now. In fact I have two, one with the light and one without. They hang on my saddlebags. The one without a light is handy as it’s a smaller construction and doesn’t rattle against a rack but the one with the light is much more useful overall and has twice as long battery life.

 

[Mike_P]

I would add with the state of many local roads the Varia pays for itself; the less time looking back means more time looking out for potholes, pothumps (overtopped filled in potholes) and ruts.

 

[Ming the Merciless]

Checking a mirror in those circumstances and processing the image means taking your eyes off the road.

Looking at a head unit takes your eyes off the road on a drop bar bike. Where as visually with a mirror you can process both forward and rear views at same time.

 

[Sea of vapours]

Looking at a head unit takes your eyes off the road on a drop bar bike. Where as visually with a mirror you can process both forward and rear views at same time.

True, but the radar / head unit combination can be set to give audible warning of approaching vehicles; hence no requirement to look at it unless you want more detail of how far way they are, for which the mirror is equally good. That's my typica operating mode.

 

[Mike_P]

I do have a mirror on my legal ebike which I tend to use once the Varia has alerted me to check where the vehicle. The ebike earns its keep on shopping and short commuting trips largely within 20 or 30mph zones so quite often the approaching car is still some time away.