Reasonable time Datamaster Michigan - What is the rule and are there exceptions? Can I get my Datamaster result suppressed in Michigan for a DUI?

In drunk driving cases, there will always be a time where a cop or witness observe the Defendant driving a car. This moment in time establishes when someone was driving, which can then be evaluated with the time that the chemical test was performed.


Recent case law eliminated the “reasonable period of time” rule in Michigan, and said the above scenario is enough to determine how much weight to give the result rather than to have it suppressed via pretrial motion by a judge. If 60 minutes pass between the first point of observed operation or 3 hours, that’s for a jury to decide, and not a judge, which has lead to more trials.


There is a remaining exception to the elimination of the reasonable period of time, which is the single-car accident, because the operation time cannot be determined, because there is no eye-witness to the driving. If someone hits a deer, and there is nobody around to determine the time, then we have no idea when the driver last operated. Unless the Defendant provides this information then there is no way to know, and courts have said under this scenario it is possible for a judge to determine that such an extensive or unknown time delay could make the test result irrelevant, and suppressible before getting in front of a jury at trial. If my client was involved in a single-car accident, and the last moment of operation cannot be determined then we may move for suppression of the results due to a lack of reasonable time period.


This technique puts the burden on the prosecutor to show the test is relevant by establishing operation. If they can’t do that then the tests are simply not reliable; my client could have been passed out in his car for three hours before someone else gets eyes on my client.