Enforcement, or the need for constant traffic surveillance, has already been raised as a problem with this approach. People tend to drive as fast as they feel safe on most streets, with the occasional unaware jerk screwing everything up. The threat of a possible ticket doesn't really work, or else we wouldn't have these problems in the first place.

A better approach is re-engineering streets for traffic calming. Basically threaten drivers with breaking or damaging their vehicle if they try too drive fast and/or in a straight line. Way more effective.

https://www.smatstraffic.com/blog/traffic-calming