Do you suppose I could convince a cop that I was going 100 MPH because I thought the speed limit was 0x65?
If a cop wants to give you a ticket he's going to give you a ticket. It doesn't matter how fast your car was going or even if it's a speeding ticket while your car was parked.
Now, the courts on the other hand... I'd love to read about someone explaining they're so overworked at programming that they instinctively think in hex. Though I'm sure someone would ask why the motorist then assumed the speeds marked in their dash were in decimal and needed to be converted.
You might have a better chance explaining that you thought "I95" was a new speed sign because everything now has an "i" attached to it.