KEY POINTS:
Luxury cars might be Lotto dreams for most, but the technical advances they introduce eventually filter down to our everyday cars.
Airbags, ABS, stability control - all were once reserved for the well-heeled, and now are fitted to entry-level vehicles.
Blind Spot Warning technology was first introduced by Volvo in 2007.
Now it's arrived as an option for several Audi models and BMW's latest 7-Series, with the new E-class due later this year to include it.
Volvo's system uses a mirror-mounted camera, Audi opts for radar.
Either way the system looks at speed differentials within a predefined area that's continuously scanned.
The size and dimensions of the area covered vary from brand to brand, but all view the road to each side and just behind the driver.
When a vehicle's detected, the type of alert varies. BMW says its set-up flashes a light and vibrates the steering wheel if you move into the path of another car, but the system wasn't fitted to the 7-Series I tried.
It was fitted to the facelift Audi A6, and proved impressive.
As you slowly pass a car, or it passes you and enters your blind zone, an orange light appears on the appropriate side mirror.
This light remains lit for as long as the vehicle is in your blind spot.
The light is not sufficiently bright to distract you, but if you flick the indicator to change lanes an eye-catching barrage of flashes warns you to stay put.
The system isn't infallible.
If you habitually change lanes without indicating it won't help, although a glance at your mirror reveals the warning light.
And not all work at every speed.
Volvo's is active from 10km/h, but Audi's fires from 60km/h and up, and is clearly designed for motorway traffic only.
Of course the warning isn't intended to replace a check in the mirrors and won't spot anything approaching rapidly, but it does act as an added pair of eyes in thicker traffic, when it's easy to forget the car holding station by your rear door.
- HERALD ON SUNDAY
