Q&A - Riding Motorcycles and Bicycles Side by Side

Let's take a quick look at the law:

Rights and duties of operator of cycle

183 (2) A person operating a cycle

(d) must not ride abreast of another person operating a cycle on the roadway,

"roadway" means the portion of the highway that is improved, designed or ordinarily used for vehicular traffic, but does not include the shoulder, and if a highway includes 2 or more separate roadways, the term "roadway" refers to any one roadway separately and not to all of them collectively;

"vehicle" means a device in, on or by which a person or thing is or may be transported or drawn on a highway, but does not include a device designed to be moved by human power, a device used exclusively on stationary rails or tracks or a motor assisted cycle;

With these three pieces of information we now have enough to answer your question.

First, a bicycle is not a vehicle, and since a bicycle lane excludes vehicular traffic, it would not be considered as part of the roadway. Nor is the shoulder part of the roadway. The shoulder is part of the highway between the right edge and the pavement if there is no solid white line to define the shoulder, or between the right edge and that line if there is. So, if you are riding on a bicycle lane or shoulder and there is sufficient width, you may ride a cycle abreast without violating the law.

You will also see that when riding abreast is prohibited, it is always prohibited, not just when other traffic is around to keep out of the way of.

Motorcycles are a different matter, as you say, likely because they are able to maintain the speed of surrounding traffic where a cycle cannot.

Motorcycles

194(4) Except when overtaking and passing other motorcycles, more than 2 operators of motorcycles must not operate their motorcycles side by side in the same direction in the same traffic lane.

This is the section of the Motor Vehicle Act that tells you it is permitted to operate motorcycles 2 abreast in the same lane.