What is the maximum slope for a bridge on an interstate?

Since this is not my area of expertise, I searched Google under the key words "maximum slope interstate bridge" to get this possible source:

http://72.14.253.104/search?q=cache:_pnq5Gew-asJ:www.modot.mo.gov/othertransportation/bike_ped/documents/modotcurrentbppolicy.pdf+maximum+slope+interstate+bridge&hl=en&gl=us&ct=clnk&cd=2&client=safari

I hope this helps. Thanks for asking.