Sign on the back of a minibus today:
Please leave 8 feet (3m) for wheelchair ramp.
You sure about that?
I think that's OK.
On signage, you don't need or want decimal places; no-one will be using a tape measure.
You just want an integer number of meet or feeters.
So if we say 8 ft, that is 2.4384m.
To round this to integer values, you might choose 2m, but since it's wheelchair access and the value of 8ft might be regarded as a minimum, you might not want to round down.
So rounding up to 3m seems reasonable to me.