Alex Wurz fears that unfamiliarity with the new slow zone regulations that will be used during the Le Mans 24 Hours could lead to an accident.
While the Toyota driver supports the introduction of slow zones, in which drivers must slow down to 60km/h, he believes that lack of experience of the system in the World Endurance Championship could cause problems.
Slow zones can be declared instead of using safety cars to reduce speeds in the vicinity of recovery or barrier repair work.
When a zone is activated, marshals display a warning board at the post before it starts, meaning drivers must not be going faster than 60km/h when they enter it.
The slow zones were trialled during the test day, as well as during Thursday night's final qualifying session, but Wurz believes inexperience could be a problem.
"I support the idea of the slow zones, especially on such a long track because it increases the racing time and distance," Wurz told AUTOSPORT.
"But it is a risk because, for example, during the test day I came down the straight at 340km/h with a dirty windscreen and a tyre vibration on my third stint so it was hard to see the board and read it.
"And one guy in front of me braked hard because he thought he had missed the first board, so there's a big risk because some might think they will get a penalty and brake hard while others decide to cruise.
"Without practice in the six-hour races and getting people used to it, there is a risk."
Wurz expects the risks to be at their highest during night running, or early in the race.
"There is big potential in the night with bad visibility," said Wurz.
"If the guys hold the board up and the reflection goes somewhere else, with all the colour around the track and things flashing, it's difficult to pick things up.
"But the even bigger risk is at the beginning of the race when everyone is still hyper-motivated and drives a little bit nuts."
There have also been question marks over some drivers going too slowly in the slow zones.
Porsche head of motorsport Harmut Kristen warned that this had been a problem in practice and testing.
"Our drivers are used to that kind of restricted pace because it's used at the Nurburgring [for VLN races and the 24 Hours] but there were some drivers that were really going very slowly, just a little bit more than 50km/h," he told AUTOSPORT.
"That's something race control should definitely be verifying with teams and drivers."
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