The Department for Transport claims that 76% of artics broke the single-carriageway 40mph limit last year, 28% by more than 10mph. The DfT report on vehicle speeds says the average speed of artics on these roads was 46mph, just 2mph less than that of cars.
DfT figures also show that 44% of two-axle LGVs broke the 30mph limits, 15% of them by more than 5mph.