In meters per second (the game measures distance in meters right), how fast can you run, drive, and swim? Obviously there are different kinds of vehicles that can go at different max speeds, so just name the ones that you know the speed of.
Here you can check the speed for every vehicle in the game. They write it's "outdated" but surely they'll update it and even if not, it's a good clue to compare vehiclespeed.
Units unknown, kmh or mph I guess.
I did not find a source, but with 3000 IFV kills I got a little experience and I'm pretty sure they differe. LAV is accelating faster than BMP, if the topspeed differs is unsure.
Check walking speed here (in progress). Running is (any weapon) 6.66 m/s Walking (pistol) 3.33 m/s
This post is older than fall-update which brought the BF3 movement in BF4. So the stats might be outdated but still give a clue.