Prominent Singapore architect Ong Tze Boon, who pleaded guilty to running a red light, willingly paid the $800 fine for the offence.
But he is appealing against the three-month ban slapped on him - underscoring which penalty hurts more, as a judge pointed out.
District Judge Carol Ling in explaining her decision, said while the fine would have sufficed, the ban would deter errant driving even though it was not mandatory.
"It would be the disqualification, with its attendant inconvenience and costs, that would serve to emphasise to the accused the need to be a more careful and responsible driver on the roads in future," she said in judgment grounds released on Tuesday.
Ong, 48, had failed to heed the red light signal at the junction of River Valley Road and Hoot Kiam Road on April 13, 2014, at 6.19am, which led to a collision with a taxi and caused slight injuries to the cab driver, Mr Ho Wai Kit, 44.
The driver sought his own medical attention and was given three days' medical leave.
The offence is punishable with a fine not exceeding $1,000 and/or imprisonment of up to six months. Under the Road Traffic Act, the court also has a discretion to impose a ban.
Ong said yesterday he was going ahead with the appeal. He added that while he may have been careless, he had not been driving recklessly or was rushing to run the red light.
Ong, who is the younger son of late president Ong Teng Cheong, is the current president of the Singapore Institute of Architects.
His lawyer, Mr Teo Choo Kee, who said his client was sorry for the accident, said Ong drove everywhere to attend to his work and his philanthropic activities, which would be "seriously hampered" by the ban.
He recently took part in the North Pole Marathon and the World Marathon Challenge to raise funds for charities supporting mental health. The philanthropic group Ong Foundation was set up by Ong and his brother in 2012.
The lawyer argued that the accident had occurred due to a momentary lapse in observation and stressed that his client was not driving recklessly or taking unnecessary risks. Ong had been looking out for people milling on the left side of the road ahead, he added.
Mr Teo also said that Ong's driving was not " so grossly inattentive or inconsiderate" as to justify anything more than an appropriate fine. It was Ong's first offence and the prosecution had no submission on sentence.
District Judge Ling, however, was "not impressed" by Ong's reasons, highlighting how he was familiar with the road as he took the route to Mount Faber for his training every Sunday morning at about 6am, and noted how at the time of the accident,traffic flow was light and visibility was clear.
"Beating a red light is a non-excusable conduct by any motorist, regardless of the reason," she wrote.
Judge Ling cited past cases which said a motorist fears disqualification more than a fine.
She quoted a 1963 judgment by a then Chief Justice, who wrote "In my experience the most satisfactory penalty for most motoring offences is disqualification. A fine is paid once and then forgotten."
Judge Ling said: "The fact that... (Ong) in the present case has chosen to appeal only against the disqualification period imposed on him is testament to the correctness of views held above." She stayed the ban pending the hearing of the appeal.