A diesel vehicle is powered by an internal combustion engine that uses diesel fuel. Unlike petrol engines, diesel engines rely on compression ignition, where air is compressed to a high temperature and then diesel is injected, causing combustion. Diesel vehicles are commonly used in commercial applications, such as trucks, buses, and vans, but are also popular in passenger cars for their fuel efficiency and durability.

As of November 25, 2024, the average price of diesel in the UK was 141.4 pence per liter, although prices can vary by region and retailer.