Manchester Evening News 13th November 2015 “Journey times on Greater Manchester roads are now up to 40 per cent slower than a year ago. The average speed on the region’s A roads during rush hour was 17.2mph in the year to September, the Department for Transport numbers show. That’s down from 17.8mph on the previous year.”
You’ll note that is not a 40% reduction – more like 4% – but the article does cite examples of individual roads where the reduction is much greater: “The worst case of deterioration is the A672 southbound in Oldham, where rush-hour speeds have plummeted to a 12.7mph average in the year up to September. That’s 43 per cent lower than in the previous year, when they averaged 22.5mph.”
Read more here.