If you commute on flat ground, you can use a lightweight racing bake and narrow tires. Unfortunately, that does not work for forest roads on my commute, so I need a heavier trekking bake with wide tires (with a lot more friction).

Moreover, if you can do 50 km/h of sustained speed, you should become a professional cycler. The world record is around 55 km in an hour. Pro cyclers can only sustain > 50 km/h speeds for shorter periods:

https://books.google.de/books?id=-TpDCgAAQBAJ&pg=PT79&lpg=PT...

Of course, short stretches of 40 or 50 km/h is doable, but most fit cyclers cannot sustain that for 3 mile stretch. So, either you are near-pro or overestimating your average speed ;).

Ps. I pass the vast majority of (clearly non-recreational) cyclers (> 95%).

I always had a trekking bike, not that it was necessary for a concrete cycle lane.

The speed is not overestimated. The overground and the car have a well defined speed for comparison. Sometimes a friend would happen to drive along on the road on his way home and be surprised that I keep up with his car.

I cycled every day for a decade. That's a good training I guess.