Why do people drive at least 10kph above the speed limit in Canada?

Hi all,

I rented a car to drive from Toronto to Montreal. On the motorway, everyone sits at least 10kph over the speed limit of 110. If I drive at the speed limit, then even those massive trucks overtake me and spread snow/slush/salt all over my the car window. So you kind of have to travel at the speed of traffic to be safe.

Even then, if I’m driving at 120kph , there are cars passing me all the time. Some of them fly by!

This is really different to Melbourne, Australia where I used to live. There everyone just went the speed limit of 100kph. Even Going 105kph would mean that you would be faster than everyone else because everyone just went the speed limit.

Why is everyone driving faster here in Canada?

This might be the wrong forum to ask this question.