do you want to draw a polygon for Milton Road that would be preferable for analysis? For the 10 in/out zones we have already (i.e. 20) I hacked together a tool to draw the zones on a map, with the coordinates accumulating as text below the map you can cut/paste which you're welcome to play with. Don't expect anything fancy:
Zone drawing tool
The current config looks like this:
"zone.id": "milton_road_in",
"zone.center":{"lat":52.224208710767265,"lng":0.13572340011593464},
"zone.zoom":15,
"zone.path":[{"lat":52.22932073333277,"lng":0.14964580535888672},
{"lat":52.23052986185695,"lng":0.14814376831054688},
{"lat":52.217490565224445,"lng":0.12638568878173828},
{"lat":52.21543968225301,"lng":0.12462615966796875},
{"lat":52.21528191810207,"lng":0.12754440307617188}],
"zone.finish_index":3,
"zone.id": "milton_road_out",
"zone.center":{"lat":52.22411669991708,"lng":0.14427428245541218},
"zone.zoom":15,
"zone.path":[{"lat":52.21541338826678,"lng":0.12690067291259766},
{"lat":52.2164388421966,"lng":0.12462615966796875},
{"lat":52.23155496676674,"lng":0.1487445831298828},
{"lat":52.22958359016109,"lng":0.15071868896484375}],
"zone.finish_index":2,
The start line is always between the first two points, similarly the finish line is the edge starting with path[finish_index].