Final answer:
In many places, the law requires that a vehicle be parked at least 15 feet away from a fire hydrant. For crossing in front of a parked car, safety depends on visibility and road conditions, not specific car lengths.
Step-by-step explanation:
The legal parking distance from a fire hydrant can vary by jurisdiction, but a common rule is that a vehicle cannot be parked within 15 feet of a fire hydrant. Regarding the safety distance for crossing in front of a parked car, it's not typically measured in car lengths but in clear visibility of oncoming traffic, and that will depend on speed limits and road conditions. It's always important to ensure that it is safe before crossing, looking for any signs of the vehicle moving and having enough visibility to see oncoming traffic.