Cyclists in next month’s Tour de France are to be banned from wearing radio-link headphones as an experimental safety measure, event organisers said on Friday.

The measure, affecting just two stages in the 2009 event – Limoges-Issoudun (July 14) and Vittel-Colmar (Jul 17) – means team managers will have to revert to communicating with racers by traditional methods including showing blackboard messages.

Radio links enabling team managers to give intructions to riders have been in general use since the 1990s.

“This measure is not being imposed by the Tour de France but represents the application of the Highway Code,” Tour sporting director Jean-Francois Pescheux told AFP. “It is aimed at preventing something dramatic happening one day.”

In another measure, staff travelling in the accompanying support cars will no longer be allowed to watch TV coverage of the race which starts at Monaco on July 4, Tour authorities said.

Police motorcyclists are also trained to signal potential hazards to the cyclists.

“In the case of an emergency affecting the course, such as a street demonstration or a roadside fire, we have in the past been able to warn the riders very quickly,” Pescheux said.