As nowadaysBecause almost everyone possesses a car nowadays, traffic has increased so much that it may represent a big problem not only for the environment but also for the safenessty of drivers. ¶

I moved "nowadays" to a position that feels more natural to me, though the position you wrote it in is not incorrect.

This essay will discuss the factors that determined a significant traffic growthhave resulted in a significant growth in traffic, and the actions that governments could take in order to prevent people from using their vehicles. ¶
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One of the main factors that has caused a growth in the traffic ofin all cities is the economic expansion of the late 1970s that allowed many people to afford a car.

Thanks to economic growth, in fact, firms working in the car industry became more competitive and started producing and selling cars at lower costs.

I feel like "in fact" is a bit out of place here. It breaks the flow of the writing.

Moreover, in order to reach thecommute to workplace,s that were usually was located far from the city center, citizens started feeling the need to buy a vehicles.

From that moment, the number of people who possessing a cars started increasing steadily. ¶
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Another factor that broughtcontributed to a higher level of congestions on the streets is the decrease in the number of people willing to take a walk instead of using asome other means of transport to move around the city.

"take a walk" usually refers to walking around for leisure, not necessity.

Researches demonstrates that people prefer to use a vehicle even if their destination is near fromclose to where they are. ¶
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In order to encourage people to use less their cars less, governments could use several measures, such as increasing the efficiency of public means of transportation, or reducing the price of the tickets required to take them. ¶
required to ride public transportation

Whereasile it could damage oil companies’ financial statements, another way to help countries reduce traffic could be adding a tax on oil. ¶

All of the three measures mentioned above could lead to the result desired results.

Flipped the last two words to sound more natural.

AsSince nowadays almost everyone possesses a car, traffic has increased so much that it may represent a big problem not only for the environment but also for the safenessty of drivers. ¶

This essay will discuss the factors that determinedresulted in a significant traffic growthgrowth in traffic, and the actions that governments could take in order to prevent people from using theirduce the number of people who use a vehicles. ¶
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One of the main factors that has caused a growth in the traffic ofin all of the cities, is the economic expansion ofthat took place during the late 1970s that allowedwhich meant many people tocould afford a car.

Thanks to economic growth, in fact, firms working in the carautomotive industry became more competitive and started producing and selling cars at lower costs.

Moreover, in order to reach the workplace, that usuallyoften was located far from the city center, citizens started feeling the need to buy a vehicle.

From that moment the number of people possessingwho owned a car started increasing steadily. ¶
to steadily increase.¶
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Another factor that brought tocaused a higher level of congestions on the streets, is the decrease in the number of people willing to take a walksimply go by foot instead of using a means of transport to move around the city.

Researches demonstrate that people prefer to use a vehicle even if their destination is near fromclose to where they are. ¶
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In order to encourage people to use less their cars less often, governments could useimplement several measures, such as increasing the efficiency of public means of transport or reducing the price of the tickets required to take them. ravel this way. ¶

Whereas it could damage oil companies’ financial statements, another way to help countries reduce traffic could be addby introducing a tax on oil. ¶

All of the threabove measures mentioned above could lead to the result desired result.