How have regulations for car and road safety changed since the beginning of the 20th century?

I have to produce a report on this for my science coursework and am a little stuck.. :S

some of the questions i need to look into are:



1) give reasons why there have been changes to speed limits for cars in Great Britain during the last hundred years



2) Who designed the first speed camera. Describe how one named type of fixed speed camera works.



3) How does the air bag work? How do air bags reduce injury?



4) Compare the features of a modern car with a very early car. Apart from air bags, describe TWO DIFFERENT safety features that are used in modern cars to reduce the risk of injury. Use ideas about speed, forces and energy to explain how these features make the car safer.



Would appreciate if you could help answer any of these questions in as much detail as you can. Thank you =]
How have regulations for car and road safety changed since the beginning of the 20th century?
The answer to each of these questions could fill a book. And all of the information is available with a little work. Good luck.

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