Guild Wars 2

When walking or running on a road or path you should gain a small swiftness boost, maybe about 5-10%.

The effect should last forever while they are on a road or path and when they step off of them it should end.

Realistically people run faster on roads or paths compared to deep snow, muddy fields or dense forests.

if it gives swiftness boost, IMO is should be at double the effect. aka 66% speed boost while out of combat.