Garmin's Varia Rearview bike radar knows what's behind you

I once had a midlife crisis; the first of many. Unable to afford a Porsche, I climbed on a bike and rode across Australia.

The scariest thing (apart from the chamois rash) was the gargantuan road trains that would suddenly appear over my right shoulder. Sadly, an elderly cyclist I met along the way met his end beneath the wheels of one of these monsters. He just didn't know it was there.

For old mate's sake as well as my own, I wish bike radar had been available back then. 

Garmin's Varia Rearview Bike Radar is the first of its kind for bikes, visually alerting both the cyclist and the approaching vehicle to assist in creating a safer environment on the roads.

What most drivers don't realise is that due to wind noise, cyclists cannot always hear a vehicle coming up behind them.

It can really come into its own on quieter suburban and country roads.

Tail-light transmitter

The Garmin system includes a rear-mounted radar tail-light transmitter, which fits on the seat-post, and a head unit attached to the handlebars using a quarter-turn mount.

The tail-light transmitter detects approaching vehicles from up to 140 metres behind and increases brightness and flashing frequency to alert the vehicle as it gets closer.

Meanwhile, the radar head unit displays a small white dot as a car approaches from behind. As it gets closer and risk increases, the dot changes colour on the LED interface. A green dot indicates that the road behind is clear. The system can track up to eight vehicles at a time.

Cyclists don't need to take their eyes off the road, as the unit is positioned in their peripheral vision.


Lightweight safety

Although the system can work independently, it can also be integrated with Garmin's Edge cycling computers, which are used in place of the head unit (the information appears as an overlay of the data screen at the edge of an Edge device).

The lightweight brigade need not worry, because the rear unit tips the scales at 63 grams and the front display unit at 28 grams; although those already using a Garmin Edge can dispense with the head unit completely.

Both units charged via a micro USB cable, and Garmin claims a radar battery life of 10 hours (in flashing mode). To save power, the radar unit is turned off automatically when you turn off the Edge unit.

In heavy city traffic the Varia might not be so useful; in fact, it may drive you nuts. But it can really come into its own on quieter suburban and country roads where wind noise and/or lack of attention can be a problem.

The Varia won't prevent a car from hitting you, but it may buy you a valuable extra few seconds' warning to help both vehicles pass safely.

Garmin charges $389 for the bundle, or $259 for the radar tail light alone.

Watch the video above to see cycling's new rearview radar technology.