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I knew I'd get called out for not including sources. Those figures are from published sources, and do not include decision time. I'd imagine that these sources are for "average" roads and "average" cars

http://www.government-fleet.com/content/driver-care-know-you...

http://www.brake.org.uk/facts-resources/15-facts/1255-speed

Car and Driver did a test with sports cars and profesional drivers and came up with 142 - 155 ft from 70mph, while my first reference quotes 245 ft (around 40% less, so extrapolating, their stopping distance from 35mph would be around 20 feet).

https://www.caranddriver.com/features/rocket-sleds-the-best-...

The average car on the road is not a sports car with performance tires and is not stopping on a clean, dry track. So I don't think it's a stretch to assume that an average car on average roads with tires optimized for tread life would be 40% worse than a $100K sports car with $400 tires that are optimized for grip rather than lifetime.



I wasn't aiming to call you out, as such. I just wanted to air my opinion, but thank you none the less for providing some sources :-)

The 45 feet from 30mph is a common figure (the UK government's Highway Code uses it as well).

The cars I tested are normal cars, but I concede I had good tyres and I always choose smooth roads to test on. Once you include:

1. Driver ability

2. Vehicle quality

3. Road quality

4. Prevailing conditions

5. 4 passengers plus luggage

I guess you can explain the difference.




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