The FIA has issued new guidance to teams to ensure cars are more clearly recognisable during Grand Prix races.
Racing director Charlie Whiting wants teams to improve how numbers and driver names are displayed on the cars. The new instructions come into effect at the next Grand Prix in Barcelona.
A decision to issue new guidance was taken at a meeting of the F1 Strategy Group and F1 Commission. Rules already existed about identification on cars, but had not been strictly enforced up to now.
The move is part of a push from the sport's new owners to improve how the sport is presented to fans, both at the circuit and on television.
Race numbers will now have to be on the external bodywork and be at least 230mm in height. F1's sporting regulations state "this number must be clearly visible from the front of the car and on the driver's crash helmet.
"The name or the emblem of the make of the car must appear on the front of the nose of the car," the regulations continue. They must also be at least 25mm in its largest dimension.
"The name of the driver must appear on the external bodywork and be clearly legible," the regulations add.
The new guidance confirms that driver names should be at least 150mm high. Teams can use official timing screen abbreviations for drivers such as HAM, VET or VER.
Referring to Article 9.2 of the regulations, Whiting wrote to teams this week to clarify the details.
"We feel that to be clearly visible the numbers should be no less than 230mm high," he said. "[They must] have a minimum stroke thickness of 40mm and be of a clearly contrasting colour to their background."
Similar advice on the display of driver names mandates a minimum stroke thickness of 30mm.
Whiting also hinted that any car whose livery was non-compliant might be ineligible to take part on that weekend's Grand Prix.
"In order to fully comply with the F1 Sporting Regulations, we expect all cars to be presented in Barcelona with this new, much clearer, identification," he wrote.
"A report will be made to the stewards concerning any car that does not comply with the above minimum requirements."