--- total (n=139) ---
avg dist: 3.5 ft
speed   : 10.1 mph
close   : 47

--- when overtaken (n=82) ---
avg dist: 3.4 ft
speed   : 10.5 mph
close   : 27

--- when overtaking (n=29) ---
avg dist: 4.3 ft
speed   : 12.4 mph
close   : 2