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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.

In addition, some cars such as the Nissan Leaf have a feature that locks the brakes at full power when there is a sudden control shift from accelerator to brakes, meaning that if you stomp on the brakes and then reduce pressure, the car will continue to brake at maximum power. This was done for two reasons: one, people hesitating in emergency situations, and two, people being taught to pump brakes, which increases braking distance in cars with ABS.

I learned about this feature when reading car forums for my car and finding threads from people who were rear-ended when they accidentally triggered this feature by slamming on the brakes when they didn't intend to come to a complete stop.

> In addition, some cars such as the Nissan Leaf have a feature that locks the brakes at full power when there is a sudden control shift from accelerator to brakes, meaning that if you stomp on the brakes and then reduce pressure, the car will continue to brake at maximum power.

Which is utterly stupid. Braking is the natural reflex, but not always the right one. I've been in more than one close call (think left turn on incoming traffic) where the correct response was not to floor the brake, but floor the gas.

> people being taught to pump brakes, which increases braking distance in cars with ABS.

Which is a mechanical turk version of what the ABS is doing under the hood.

That seems deeply unexpected. Was there any resolution or response from Nissan in any of the cases you read about?

> I'm talking about optimal conditions here, wet roads would change things obviously but each of these cars was able to stop within it's own car length (around 15 feet) from 30mph, simply by stamping on the brake pedal with maximum force, triggering the ABS until the car stops

How did you measure that? Because plugging these figures into a uniform acceleration calculator, 50km/h to 0 in 4.47m requires a deceleration of 2.2g but "Analysis of emergency braking of a vehicle"[0] experimentally measured very best case deceleration as barely scraping 1g (with ABS at 80km/h, significantly lower at lower speeds or without ABS).

[0] https://www.tandfonline.com/doi/pdf/10.1080/16484142.2007.96...