Chief Constable Hughes - the county's most senior ranking policeman and the country's top traffic officer - faces a possible ban if found guilty.
Today road safety group Speed Safe, which is campaigning for an improved road safety policing policy and says speed cameras should not be relied upon, said Chief Constable Hughes should resign from South Yorkshire Police and as head of roads policing issues for the Association of Chief Police Officers.
Speed Safe founder Paul Smith said: "His position is completely untenable.
"I demand his resignation, both from the ACPO road safety committee and from his office as Chief Constable of South Yorkshire.
"He has brought the entire police service into disrepute. How can the public have confidence?"
He said that if convicted the Chief Constable should "be given a taste of his own medicine and banned from driving" and insists public money should not be used to pay for a chauffeur for him.
A spokesman for road safety charity Brake added: "If Mr Hughes is proven to have been speeding he must consider his position very carefully. To remain, would undermine his own traffic officers whose job is to ensure that speeding drivers do not cause misery on our roads."
Chief Constable Hughes has received a notice of intended prosecution for an alleged speeding offence committed in North Wales while he was on a Bank Holiday break in May.
He was clocked on the A5, near Chirk, and his case is due to be heard before Wrexham magistrates next month.
A South Yorkshire Police spokeswoman said: "Chief Constable Med Hughes has received a notice of intended prosecution in respect of an alleged driving offence in North Wales in the early morning of a Bank Holiday Monday in May while he was on holiday.
"No summons has yet been received."
If convicted, the court has the power to fine Mr Hughes, who is originally from Cardiff, up to £1,000 and even issue a possible driving ban.
Mr Hughes is head of roads policing for the Association of Chief Police Officers - a role which involves liaising with Government officials on policing the roads and speaking as a national police figurehead.
His role involves pushing through new road policing initiatives, policy changes, law changes and overseeing product development.
When he was appointed two years ago he had six penalty points on his licence for two speeding offences.
Mr Hughes has publicly admitted breaking the limit twice and revealed he was issued with £60 fines on both occasions, although he never disclosed the speeds he was travelling at.
He was first caught while travelling to work along the A61 in South Yorkshire at 6am and received his second ticket a few months later after a portable camera clocked him during a break in south Wales.
Despite his record, Mr Hughes has called for even stricter crackdowns on speeding - suggesting all cameras should be hidden.
In June he suggested police forces should consider introducing "less conspicuous" speed cameras as a way of making more motorists slow down.
He said more lives would be saved if drivers did not know where they might be caught speeding and said it was "strange" cameras could be so easily identified.
In June he said his penalty points had expired and he would have quit his ACPO role if he had reached nine points for a third offence.
Mr Hughes refused to comment about the latest incident.