Here's the basic idea:
First determine the distance between the chasee and the chaser. The chasee can use obstacles to try to gain distance or impede the chaser. Obstacles are determined by the location. Distance is gained or lost in 10ft lengths. The chase ends when the chasee is caught, gains x number of lengths, or the chaser gives up.
#1 chases #2 into an alley. #2 has a 30ft lead on #1.
Obstacles: Crates and a fence
Option 1 - #2 can pull the crates over to cause #1 to have to successfully dodge the crates or loose a length while #2 climbs over the fence.
Option 2 - #2 can just try to climb the fence faster than normal. If he succeeds he can gains a length, if he fails he looses a length.
I plan to develop the idea and post the tables for specific locations. Look for Small Villages, Medieval Style.