What I read back when the bans were lifted around here was that cell phone use correlated with people opening the car door and rummaging around, which created a static electricity buildup, and that that was the real fire risk.
Source: workplace safety videos I was forced to watch, years ago
Specialty tires like you find on drag cars do not. This is why you also see grounding straps dangling from drag cars -- to keep the driver from getting a shock when they step out after a run.