PARIS (AP) — A wildcat strike has severely disrupted train travel around France, as railway workers demand better security after a recent accident.

Traffic was particularly tangled Friday in southern France and western France, around Lyon and in the Paris region, according to the SNCF national rail authority.

Paris suburb trains, including the RER B to Paris-Charles de Gaulle airport, were severely disrupted, the SNCF said.

The SNCF advised travelers to postpone their trips or use other means of transport. Many French families had made plans to travel Friday as two-week school holidays were starting.

The CGT union called for the walkout after a truck-train collision in eastern France Wednesday left 11 injured. CGT official Laurent Brun tweeted that the accident was “the final straw” after a string of other incidents, and that train drivers don’t want to die on the job or have “passenger deaths on our conscience.”

The action comes amid a season of strikes and protests over President Emmanuel Macron’s plans to overhaul France’s complex retirement benefits and other policies.