Why do we need speeding laws?
why do we have drinking and driving laws?
why do we have a work safe policy?

why do we need speeding laws? - if everyone drove at the speed they like, then some people would be going down the road 35 mph, some at 100 mph, some at 15 mph, and that would create traffic, chaos, and accidents.

why do we have drinking and driving laws? - when we drink, our decision making is dulled, our senses are dulled, and we get sleepier / inhibitionless. also, our concentration gets shot after alcohol.

why do we have a work safe policy? - work safe policies are made to protect employees from danger, and to protect employers from lawsuits.

Why do we need speeding laws? 
Speeding laws protect - not only the driver - from crashes, fatal injuries and even death, but it also protects animals, and humans alike that are on the road walking, biking or running alongside the vehicles, allowing for less injury.

Why do we have drinking and driving laws?
It is a terrible idea to drink and drive, this law also protects - not only the driver - from crashes, fatal injuries and even death but also - like above - animals and humans alike. Drunk drivers usually go rather 'off' when they're drinking and driving, making all situations very dangerous. 

Why do we have a work safe policy?
This law enables people to the right to being safe and knowing about safety issues and acts that must be taken to avoid injury, fatal injuries and death in their workplace.