The male rider suffered ligament damage and severe swelling to his left leg, while his female passenger's left tibia was broken.
Defence lawyer Tim Braithwaite said Jacobs had since "grilled himself" about how it happened.
"He describes himself as a cautious driver usually."
Mr Braithwaite said Jacobs had concluded he must have mistaken the approaching bike's headlights for those of a car in the distance.
"It's an optical illusion."
The crash had affected Jacobs financially and emotionally and he had lost about $20,000 because of his inability to work in Australia while the case was before the courts, Mr Braithwaite said.
Jacobs could pay the extra $3000 reparation but would have to go into debt, he said.
Jacobs addressed the judge, saying at his age and with a shoulder injury it was difficult to get work as a builder.
"Please don't be under the illusion that it's easy for me at all," he said.
The judge replied "no it isn't".
"But it hasn't been easy for the [victims] either. They are the innocent parties here."
In determining sentence, Judge McGuire noted Jacobs' otherwise unblemished record.