# Re: Emergency braking and bird anatomy [was: Re: DVD copying and CSS]

```Pigeon wrote:

```
```On Sun, Feb 22, 2004 at 02:23:38PM -0800, Paul Johnson wrote:
```
```On Sun, Feb 22, 2004 at 05:20:48PM +0000, stephen parkinson wrote:
```
assume perfect driver, what is difference in stopping distance 30mph cf 35mph
```According to the ODOT Driver Manual[1], page 39 (in the PDF, 33 on
printed page), you add another 80 feet to your stopping distance going
from 30 to 40 MPH.  I also learned that Oregon's speed limit silently
raised from 65 to 70 MPH in this edition of the driver's manual...
```
```
The UK's Highway Code calculates stopping distances from the equation:

d = v + 0.05(v^2)    (d in feet, v in mph)
```
which gives an increase, from 30mph to 35mph, of 21 feet 3 inches - so
```the advert's claim is 3 inches short :-)

It also gives you "fudge factors" of x2 for wet and x10 for icy
conditions. Doesn't give you one for locking the wheels though...

```
so basically 5 mph extra from 30mph will transfer the momentum involved in stopping over the next 20ft to some silly sod who got in the way. bags of skin just do not bounce very well, istr to recall my sister rolling quite a way from a milk float impact, but then she was ball shaped anyway at 9 yrs old
```she's not that shape now though :-)

stephen

```