At the moment, 45 per cent of vehicles on the roads don't have their ITV inspection up to date. This compares to 20 per cent before the pandemic.
The findings come from the AECA-ITV, the national association of test centre operating companies. It is urging motorists to set up their appointments as the extension period for delayed tests from the first lockdown last year expires on 2 March.
The group says its members have gone to great lengths to increase capacity at testing centres by between 30 to 65 per cent.
"The ITV saves lives," said the head of AECA-ITV, Guillermo Magaz.
According to analysis by Madrid's Carlos III University, ITV tests avoid 540 deaths from accidents or pollution a year, and if every vehicle was up to date 80 more lives could be saved.