Why Has Diesel Fuel Been More Expensive Than Gasoline?

Diesel engines are heavier so a 2500 cc diesel engine will be heavier than a 2500 cc petrol engine because stronger parts are needed for their operation, this extra weight will reduce their performance levels.
The turbo diesel engine will gain a higher percentage of the increase in horsepower but will not automatically become faster than a similar sized gasoline engine with a turbocharger offering the same amount of boost.
Complexity is reduced in a diesel engine as there is no ignition system but this is not a total advantage as they can be noisy and may require frequent maintenance intervals when compared to a petrol engine.
Diesel engines can pull or carry heavier loads for longer distances because they produce more torque. That would
The crude oil pumped out of the ground is black liquid called petroleum. This liquid contains hydrocarbons, and the carbon atoms in crude oil link together in chains of different lengths. http://www.eia.gov/tools/faqs/faq.cfm?id=9&t=5 Why has diesel fuel been more expensive than gasoline?
On-highway diesel fuel prices have been higher than regular gasoline prices almost continuously since September 2004, a break from the historical pattern of diesel fuel prices usually being lower than gasoline prices except in cold winters when demand for heating oil pushed diesel fuel prices higher. The main reasons why diesel fuel prices have been higher than gasoline prices in recent years are:
High worldwide demand for diesel fuel and other distillate fuel oils, especially in Europe, China, India, and the United States, and a tight global refining capacity available to meet demand during the period of high economic growth from 2002 to mid-2008.
The transition to less polluting, lower-sulfur diesel fuels in the United States affected diesel fuel production and distribution costs.
The Federal excise tax for on-highway diesel fuel of 24.4 cents/gallon is 6 cents per gallon higher the gasoline
This means significant investments in new technology and several distillations before the finished fuel is deemed acceptable by government inspectors. All of these additional regulations and high-tech equipment can cost billions of dollars, and these expenses are often passed onto consumers through higher prices.
There are also higher federal excise taxes placed on diesel fuel compared to standard gasoline. Some critics suggest the federal government is less eager to impose higher taxes on millions of private drivers than thousands of commercial drivers who use a less popular fuel. Part of the reason diesel fuel is more expensive than gas is the total amount of federal and state taxes added to each gallon.
In many other countries, diesel fuel is still much cheaper than petrol, and there are significantly more diesel-powered passenger vehicles on European and Asian roadways. If more drivers in the United States were willing or able to switch to diesel-powered vehicles, the price per gallon of diesel fuel might begin to fall below that of gasoline. More refineries would have the financial incentive to process more diesel fuel during peak driving months, and more fueling stations would offer standard diesel or the more ecological friendly bio-diesel at competitive prices.