Criminal lawyer Paul Barnett was allowed to stay on the road despite it being the third time he had been clocked speeding in just 18 months.
He told the court he needed to keep his licence so he could drive around the country visiting his clients who are being held behind bars.
And he said the closure of Peterhead Prison in December meant his clients had been dispersed to other jails and his annual mileage would increase as a result.
Barnett, 41, of Cedar Place, Aberdeen, admitted speeding at 98mph in his 3.2 litre Audi TT on the M90 Perth to Inverkeithing road on August 5 last year.
The lawyer had initially been charged with speeding at 101mph but the Crown accepted a guilty plea to the slightly lower speed at Perth's Justice of the Peace court.
Fiscal depute Jim Eodanable told the court police officers spotted Barnett's sporty Audi travelling at well above the 70mph limit and pulled him over.
Solicitor George Mathers, whose firm Barnett works for, said: "He was making his way to Polmont to see a client. At Polmont, like other institutions, you have to arrange in advance when you can go there.
"You make an appointment and that is strictly adhered to. If you don't get there in time you don't get to see your client. That is the explanation why he was in a hurry."
Mr Mathers said Barnett slowed down immediately and fully co-operated with the police. The lawyer's driving licence is extremely important to him, the court was told.
Mr Mathers added: "He does tens of thousands of miles a year in connection with work and for social reasons involving his young son.
"Things were made worse recently because a number of clients were in prison near Aberdeen, but that closed and they have been transferred to other prisons around the country.
"He does drive a huge number of miles a year and his licence is important to him. Losing it would place a huge burden on others in the firm."
Mr Mathers asked the court for Barnett to be given the maximum number of penalty points on his licence rather than being banned from the roads.
The solicitor said: "He would be very near totting up and he will have to be extremely careful for the next three years."
Barnett, who had six points on his licence due to speeding offences from 2012, in February and June and who was also clocked speeding in 2009, was shown mercy by JP Christine Grant.
She told him that because he had pleaded guilty she would limit his penalty to five points, giving him a total of 11 on his licence. Barnett was also fined £320.