Michigan has developed a set of 11 guidelines, called warrants, to determine whether a traffic signal is needed. The most closely reviewed warrants are based on three questions.
- Is sufficient traffic coming from the side road to require a signal?
- Is the main road's traffic flow so constant that side-road traffic cannot enter or cross the main road?
- Have a significant number of accidents occurred at this intersection?
Requests for traffic signals are reviewed, with the decision based on the warrants. Petitions are not a basis for the installation of a new traffic signal; however, they are helpful in bringing an intersection to our attention.