Speed

These are the numerical values for the various settings related to movement in Half-Life 2.

Speed
Crouching: 63.33 (2.7 mph)
Walking: 150 (6.4 mph)
Running: 190 (8.1 mph)
Sprinting : 320 (13.6 mph)
Surface Swim Speed: 152 (6.5 mph)
Surface Swim Fast Speed: 256 (11.3 mph)
Surface Swim Slow Speed: 120 (5.1 mph)
Aux power flashlight: 43 seconds

Sprinting
Speed: 320 units per second (13.6 mph)
Max Distance: 2560
Max Duration: 8 seconds
Recovery time: 8 seconds

https://web.archive.org/web/20200916060946/https://developer.valvesoftware.com/wiki/Dimensions