If you examine the prompt given more closely, then you will see that you are being asked to discuss openly the general information. Therefore, I think this part:
many developing countries.
is off-topic. This discussion is all over the globe.
To begin with, increasing the price of haulage power is an exciting possibility but not reliable. Firstly, this measure, absolutely, affects directly to drivers, namely, motor drivers and car drivers. That is to say, as the petrol become costly, there will be a short-term deduction in its consumption which directly affects transport usage. Hence, traffic jam can be decreased considerably which brings about some beneficial impacts to the environment. On the contrary, since people find it hard to travel to work there would be a long-term deduction in national GDP. To put it simply, people need more reasonable means of transport in order to support their work
This would be nice if you compose this paragraph using:
Firstly, (supporting idea)
Example, (an obvious example of this can be retrieved from: who? what? how many? when? where? result?
second idea (supporting idea)
Finally, (supporting idea)
What other measures
If I were you, I would mention two measures, which are from government and individuals
To put it in a nut-shell,
I know this concluding signal from students all over the world. However, this is not allowed in IELTS.
Use the simple one: In conclusion..., Given this evidence,... etc.
Overall, you write good.