How are Speed Limits set and changed?

In the State of Maine, state law authorizes the Maine Department of Transportation as the only legal entity to create or change a speed limit. The Town is not able to change the legal speed limit on a roadway, only to modify/add regulatory signage to help enforce that speed limit. 

Maine DOT establishes the speed limit within the Town of Brunswick. Maine DOT uses the Manual for Uniform Traffic Control Devices (MUTCD) as the guideline for setting speed limits, as that is the national standard published by the US Department of Transportation’s Federal Highway Administration. The short summary of how the speed limit is set is a speed study measures the average vehicular speed over a number of days, and then the speed limit is based on the average 85th percentile speed. The 85th percentile has been extensively studied to be the basis for setting a speed limit on a road segment. Additional factors such as driveway density, road geometry, and other characteristics are also considered. This is the standard traffic engineering process throughout the country. 

If a citizen is concerned with altering the legal speed limit, they can speak with the Town Engineer's office who can arrange for a speed study. Then the summary of findings are provided to the town council. The town council can review the study and choose to formally ask Maine DOT to conduct a study to revaluate the posted speed limit. Please note that Maine DOT can say that their own study supports no change, that their study does recommend lowering the speed limit, and on rare occasion they have even actually raised a speed limit that was requested to be lowered based on their independent study.

For more information, please visit the Maine DOT’s posted speed limits at this website: and more general information here:

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1. How do I get a Street Opening Permit?
2. How do I get an Entrance Permit?
3. How are Speed Limits set and changed?