Effective Length for a Road Plate with wheel load

[see_gen_notes]

I'm designing a road plate and I want to know the length of the plate can I use to resist bending from a wheel load? The plate will be simply supported and free on the other sides.

 

[bridgebuster]

Different agencies have different requirements. One DOT we work for allows an A709 Gr. 50 plate 1 1/2" thick is good for an opening up to 10', with 10"(min) contact length, for a 16k wheel+ impact. Another agency we work for limits deflection to 3/4"; another uses 1" plate A36 up to 5' with 12" (min) contact.