Should work but ... if you have enough water flow to create problems with the crossing you've used for years, I'd probably consider a couple loads of rip rap on the down stream end of the slats to keep the flowing water from creating an overfall and hole and thus undercutting the downstream edge.  If this happens, water can continue moving dirt out from under the slats do to the holes in the slats.  Soon it could become sloped to the downstream side.  Only way to fix then would be to take slats out and start over.

You'll have to deal with a little silting on top of the slats if your rip rap is a tad higher, but thats better than a hole on the downstream side, that erodes back up under your crossing.