Ann Arbor needs to re-assess posted speed limits on it's main roads. In 2006, the Michigan Legislature passed Public Law 85 which revised the Michigan Vehicle Code. This law created a new method under which city officials determine the safest and most accurate speed limits along main roads. It is based on using a sliding scale of access points (driveways and intersections).
In addition, the State of Michigan has previously adopted the State Police Uniform Traffic Code which in conjunction with Public Law 85 helps to establish how the state determines what speed limits to post and where. This code identifies that the safest speed limit to post is one which occurs at the 85th percentile traffic speed. This percentile establishes the majority of people (85%) as legal so that police can focus their enforcement on the small majority who are speeding.
As James C. Walker wrote in his recent op-ed at AnnArbor.com, "The Ann Arbor City Council and Project Management Department do not follow either method under state law." Walker notes that instead the city is posting unrealistically low speed limits, not taking into account the State Police Uniform Traffic Code or Public Law 85. Since 2006 when Public Law 85 was adopted the city has done nothing to change its main road speed limits and should be held accountable. This non-compliance results in speed limits that can be unsafe to all drivers and cause many different types of accidents.