Sunday, June 24, 2007
LANCET DOES BRAKE DISTANCES
The Age reports:
The risk of drivers crashing doubled if they were speeding 5 km/h over the 60 km/h limit, the Transport Accident Commission said.
Ridiculous. The TAC also claims that the “stopping distance of a car with good brakes travelling in dry road conditions” at just 50 kmh (30 mph) is 35 metres, or 115 feet.
Hmmm. This Michelin site reports 40 metre stops from 50 kmh on snow-covered roads using winter tyres; you’d expect much better than a 5-metre advantage in the dry. And a road test of the large Chevrolet Silverado reports a stopping distance from 100 kmh (60 mph) of 39 metres; only four metres further than the TAC believes is typical for a well-maintained car braking from half that speed.
Subaru’s 2002 Outback Sport is a reasonable example of a routine road machine, such as might be found on Melbourne’s streets. Its measured stopping distance is 38.7 metres - again, from 100 kmh. With rear drum brakes. What pedal are the TAC’s testers hitting?
(Much thanks to reader Blink, who raised doubt over the TAC’s claims after I’d cited them in an earlier post.)