please help translate this

[Tim brtlnk]

I found some pages on the web from an unfinished Tintin comic, titled: "Tintin et le thermozéro''

Tintin and Haddock are in Italie on a road and Haddock was almost hit by several cars...

I translated most of the text but I don't know what this part means:

Haddock: Il a manqué me tuer, ce zigomar-là! Mais qu'est-ce qu'ils ont à rouler comme des fous? on devrait interidre la route à tous ces chauffards qui dépassent le 60 à l'heure!

Tinin: De ce côte-là, vous seriez en règle: il n'y a que dans les fortes descentes que mélanie frôle le 70!

Can you please help me to translate it?

Merci beaucoup!

[George Hunt]

Ok  Just a rough attempt:

Haddock: He nearly killed me,that "zigomar(!) ! What are  they doing driving like mad men. They should  keep those hotheads (I  guess) that do over 60 kph off the roads!

Tintin:

Over there you would be right. Melanie (name of the car?)  only gets close to 70 in the  steep inclines!

Hope that works?

[Tim brtlnk]

Thank you very much, great!

[Vedas]

Hello,

chauffards is rather reckless drivers or roadhogs

[George Hunt]

I wonder what it comes from?I guessed it came from "chaud" but it could be "chauffeur" I suppose  -or maybe something else.

[Vedas]

Yes, it comes from "chauffeur" + derogatory suffix "ard"