The biggest fall in average speeds was seen in Peterborough, where cars in off-peak hours had been travelling at 38.8 mph in 1993 and now only manage 33.7 mph.
Not all cities suffered. In six areas, there has been a significant increase in average speed. In Derby, speeds rose by nearly 5 mph. In Tyneside, the absence of roadworks when surveying took place in January 1997 led to a rise in average speeds of more than 3mph during the rush hour.Reuse content