The government will raise more tax in order for them to generate more revenue and the tax rate will be a progressive tax and they likely to use a highway than the poor since it links to the city area where they work.
People who have car in Thailand considered as a rich people, which means that the poor tend to use public transportation such as sky train and buses.
The government in Thailand is more likely use the revenue that they have to maximize their own interest according to public choice economics theory.
Hence, the government will spend that amount of revenue in order to gain the vote for the next election but not maximize the society interest