Well, as a good software-engineer-and-qualified-lawyer friend of mine has said, "the power of the law is in its capacity for vagueness".
I often wish law was written more like a computer program, with lots of unit tests up front. But I have no idea how to actually achieve that. Real life is so much more complex than input to any computer program that an attempt to formalise law even more than it already is formalised would just result in it being totally incomprehensible to the people who have to follow it (as opposed to mostly). Plus the man on the street tends to get very angry when people who are "obviously" guilty get off on a technicality.
I've always thought a good starting point would be to hook up Watson or similar software up to LexisNexis or Westlaw. Would be lovely to run a new ToS or Privacy Policy through such software and see where it breaks down.
And those signs aren't even what was intended. "Motor vehicle"? Oh, okay, then my Nissan Leaf is not allowed because it has an electric motor, but my motorcycle is okay because it uses an gasoline engine, not a motor.
But I know what they meant, and keep my motorcycle off the bicycle trail. However, the pedant and software developer in me is bothered just a little when I read those signs.
You can probably find an online copy of the city ordinances that specify exactly what "motor vehicle" means in that context. An interesting thing I noticed in one city is that it's technically illegal to drive certain (stock, unmodified) models of car above 3000RPM due to noise ordinances prohibiting exhaust bypass systems.
I often wish law was written more like a computer program, with lots of unit tests up front. But I have no idea how to actually achieve that. Real life is so much more complex than input to any computer program that an attempt to formalise law even more than it already is formalised would just result in it being totally incomprehensible to the people who have to follow it (as opposed to mostly). Plus the man on the street tends to get very angry when people who are "obviously" guilty get off on a technicality.