Windsor Police   standard here in the city for this is typically 8 feet and that is the number that would be ideal to use here.
POSITIVE OUTCOME The addition of a number of these "Parklet Patios" are very likely to produce the public safely outcome of slowing (traffic calming) vehicular traffic that passes through the area. The reason for this is that the placement of the patios closer to the roadway, particularly if there are a number of them over a longer stretch, will serve to elevate "spatial texturing" for drivers. This will cause a visual narrowing of the remaining portion of overall roadway space which will cause many drivers to naturally slow down as they approach.When a driver slows down, this has the effect of increasing the amount of stopping distance available to safely stop the vehicle when necessary.
ADDITIONAL COMMENTS In regards to below, I believe WPS’s Barry Horrobin, Director of Planning and Physical Resources, has responded on behalf of WPS but again our main concern is public safety. We would ask that the if a detoured walkway/parklet is built through a parking lane (on a roadway), the detour must be robust on both ends, especially the side facing oncoming traffic as this will protect those who are utilizing it. A concrete/or solid barrier would be ideal on either end of the detour/parklet. Visibility is also a concern but that seems to have been addressed with reflective tape and lighting. This is a necessity to ensure the safety of users and approaching vehicles.
Also it is very important that these walkways/parklets do not obstruct police response: namely Erie St BIA (1 and 3), Ottawa Street BIA (alley ways) (2 and 6); Wyandotte Town Centre BIA; Ford City; Pillette Village, Downtown BIA (I did not see a request for road closure) and Ibelieve Sandwich BIA.