The 33-year-old Ngunnawal man has been charged with culpable driving causing death and drug driving and will appear before the ACT Magistrates Court on December 18.

Police will allege the man had methamphetamine in his system at the time of the crash.

Ms Salthouse, 71, was riding a wheelchair accessible motorcycle on Commonwealth Avenue bridge when it was involved in the incident with a car on July 20.

The 2020 ACT Senior Australian of the Year was prominent in the community and a passionate advocate for people with disabilities.

ACT Policing superintendent Corey Heldon said the alleged offender had been cooperative with police throughout the three-month investigation.

He has not been taken into custody but has been summonsed to appear in court next month.

She said it had been a "technical investigation", which required "expertise to understand the physics of the collision".

There have been six deaths on Canberra roads this year.

Superintendent Heldon urged people to drive carefully as state borders opened up and people began travelling over the summer period.

READ MORE:

"Every one is too many," she said.

"We don't want any more. It's difficult for my officers who have to attend but you know it radiates out to the community.

"It's actually families who are affected by this and it causes pain and we'd like to avoid that as much as possible for the community."