Can anyone tell me why diesel fuel is more expensive than high test gas when it requires less refining.?

Two words: Corporate Greed!! Diesel cars get much better gas mileage than cars that run on regular fuel. Demand? I doubt that is an issue considering one big rig holds up to 200 gallons of gasoline and are needed to keep the economy going unlike a personal car. The oil industry is taking advantage of our dependency on these fuels. If everyone qiut driving cars, big rigs will still be needed to transport things we need and want in our everyday lives. Truckers are hurting more than the rest of us and it's causing everything else to go up in cost as a result. Imagine spending around $1,000 to fill up a vehicle that gets about 6-7 miles per gallon. Yeah it goes a pretty long range but big rigs average about 800,000 miles a year. They have to keep moving to make money. A bathroom break could be a $40 loss in profits. I'm not a trucker but many people in my family are. Also, outside the U.S and Canada, diesel fuel is more popular than regular gas in most countries around the world.