A study by UtrechtUniversity in the Netherlands has shown that driving while tired can be as bad as driving while drunk. The study showed that after just two hours behind the wheel, drivers made the same mistakes they would if they had 0.05% blood alcohol content, which is more than half the UK legal drink drive limit. After three hours’ driving their performance corresponded to 0.08% blood alcohol content, the national limit. By four and a half hours, it was equivalent to 0.10%. Driver tiredness is thought to be responsible for 20% of road deaths in the UK.