Does the encounter rate increase while running or riding a bike?

Solution 1:

Bulbapedia states that using the Running Shoes does increase the wild encounter rate. Furthermore, in the games (at least in Pokémon HeartGold I'm sure) it says something along the lines of running in the grass creates noise and startles more Pokemon.

Anecdotally, when I walk through a patch of grass, most of the time I do so without encountering a single Pokemon. But running through the same grass I almost always encounter at least one wild Pokemon.

Solution 2:

I did a stastical t-test on the number of pokemon that one sees over 200 steps and I found that the amount of pokemon you see is different and lowered when walking vs on a bike. Over that 200 steps I found that you see on average 14 pokemon while on a bike and 6 while walking.