Changes to the rules in 2011 solve Pirelli's dilemma about how to continue developing its F1 tyres.
The Italian marque used a 2009 Toyota and testers Nick Heidfeld, Pedro de la Rosa and Romain Grosjean to develop this season's tyres, but decided that the car is now too old to be useful to the latest generation of single seaters.
The World Motor Sport Council on Tuesday approved a rule tweak so that experimental tyres can be tested by the teams during Friday practice sessions at grands prix.
"Without this potential opportunity we would be unable to test with a current car and would be relying solely on a previous generation vehicle," said Pirelli's Paul Hembery in Barcelona.
Meanwhile, he admitted he was not happy on Tuesday after hoping for warmer weather to prove the durability of the tyres to concerned teams and drivers.
"It's even colder than the last time we were here," the Briton told La Gazzetta dello Sport.