Does my car use more fuel at 20mph than at 30mph?

In North London, where a new 20mph speed limit has been introduced, some drivers are noticing more frequent fuel stops. While it's true that lower speeds generally consume more fuel per mile, the significant change in driving habits and potentially more stop-and-go traffic could be contributing to the perception of higher fuel consumption. This shift matters as it impacts both individual drivers' fuel costs and broader discussions about urban traffic management and environmental impact. The article explores whether the new speed limits are as fuel-efficient as they're intended to be.