IIRC, used to be [dawn of time, around 1970] that interstate standards were
4% max EXCEPT where it wasn't feasible, like mountains and such.  You simply
couldn't build a 4 or 5 % grade over the three major mountain chains in the
US for less than the national budget.

Mike

On 2/3/04 6:25 AM, "David Brodbeck" <gull@GULL.US> wrote:

> On Mon, 2 Feb 2004, Kim Brennan wrote:
>
>> Unfortunately, US interstate highways use a lesser standard than the
>> Autobahn in Germany. Grades are steeper (6% though waivers can make
>> that higher, versus 3%) and the roads are straighter (and more boring).
>
> I wonder what the maximum grade on the Interstate highway system is?  I
> think I've seen up to 8% in my own travels.  I seem to recall seeing 12%
> posted somewhere, probably a U.S. route or county road.
>
>
> David Brodbeck, N8SRE
> '82 Volkswagen Diesel Westfalia
> '86 Volvo 240DL wagon
>
>