Renault's Nico Hulkenberg believes the high degradation rate in Montreal of Pirelli's soft compound could lead to major pitlane congestion in Sunday's race.
Plenty of drivers reported a drop-off of performance and excessive wear of the soft tyre during Friday's practice sessions, with FP2 pace setter at the forefront of the complaints.
Part of Friday's degradation was perhaps due to the dusty condition of the Circuit Gilles Villeneuve's tarmac, but Hulkenberg feared that if the track did not significantly improve in the upcoming sessions, an early mad dash and tyre swap could take place on Sunday.
"There is going to be a traffic jam on lap six in the pits," the German told Motorsport.com when asked about the soft tyre's durability.
"We will need to introduce some traffic lights!
"But usually as well today, the track started in a really poor condition and got better just through the day constantly.
"With more running tomorrow, and then we see it every year that by Sunday things are in a much better place than Friday very often. Maybe it won’t be as bad as it seems now."
Renault team mate Daniel Ricciardo practically took for granted that the Canadian Grand Prix will be two-stopper.
"Track temp is getting hotter for Sunday, so the days of an easy one stop around here, we might not see that this weekend," he said.
"I am happy about that if that is the case because you can overtake here, so any kind of two stop will open things up.
"There was also a big variation between teams. It looked like some cars could hold a high 1m17s and others were dropping into the high 19s, so if we are forced to stay out on that and do a one stop then you might see some pretty big differences across teams."
Pirelli's Mario Isola reckoned that a few bold drivers could rely on the medium tyre to make the Q3 cut on Saturday afternoon, and dispense with the C5 soft compound altogether on race day.
"It is not convenient to stay on a soft that is degrading," said Isola.
"That is why I believe someone will try to be on medium/hard in the race.
"But if the delta [between the medium and soft compound] is more than one second, in that case I am not sure they will try to qualify with the medium because it is too high a risk."
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