Prices for gasoline and diesel have more than doubled since the US-Israel conflict with Iran began in February, affecting transport businesses, farmers and anyone who drives a vehicle in America.

Ahead of the critical midterm elections, there have been growing calls for more to be done to reduce the price of fuel, and US President Donald Trump has made several comments and announcements aimed at getting costs down.

The question is: what is he able to do with just a few weeks to go before election day - and will it work?

Why does Trump want to reduce gas and diesel prices?

Trump's announcement of a waiver on the use of red dye diesel at a campaign stop this week underscored the importance of gas prices in a midterm election dominated by affordability issues.

The election comes as there is widespread public concern over the rising costs of fuel, food and other goods. Voters have tied the issue to Trump and his party, weighing down Republicans running in November.

Polls show a majority of Americans disapprove of Trump's handling of the economy and the war in Iran, which has contributed to high diesel and gas prices in the US.