French road sign - looks like an exploding car

[SlightlyMadScotland]

What does it mean?

No GPL fuelled cars allowed. Not sure what GPL is in English? It's a specific type of fuel.

You are wonderful!

(it could be lpg in UK)

Why do you want to know?

Idle curiousity or a quiz question?

Seems like a strange "HAVE to know" for a Tuesday!

2 reasons.

1 residual curiosity from whne I was in France in summer...I thought it would be obvious that they didn't like exploding cars anddisn't seen the need for a million signposts!

1. It has just come up in a quiz (or at least a virtually identical sign from a different country has.

I have wanted to know this for years!
Thank you so much for asking.