Background on the Minnesota Speed Monitoring Program

In 1974, the National Maximum Speed Limit of 55 mph was implemented for all roadways within the United States as a temporary response to a severe fuel shortage. This prompted not only lower traveling speeds, but also a significant decline in traffic fatalities. With these favorable effects, Congress maintained the National Maximum Speed Limit, not only as an energy measure but also as a safety principle.

Within the same year, state enforcement of the 55 mph speed limit law became a prerequisite for receiving Federal funding for highway projects. States were required to achieve a 50% compliance rate for the 55 mph speed limit or else incur sanctions against highway construction funds. Programs were implemented to monitor speeds as a measure in determining this compliance rate.

In 1987 the National Maximum Speed Limit was amended to allow states to raise the speed limit to 65 mph on rural freeways. This may have been the result of the decrease in compliance scores along with the change in the attitude of the public. The Federal Highway Administration did not require states to monitor the 65 mph roadways until Federal Fiscal Year (F.F.Y.)1995.

From the 1980's through F.F.Y. 1994 the speed monitoring program used basically the same sites, categories, and calculations with only few sites being changed because of roadway mileage in each category and switching to some automated sites. A Lotus program developed by Mn/DOT was originally used to calculate the results, but in the final years a Paradox program was used. There were 34 sites, some were monitored every quarter and were considered the base sites, while others were random sites that were monitored only once a year.

In F.F.Y. 1995 the monitoring program was changed drastically. A Lotus program sent out by the FHWA was used to perform the calculations. The categories were changed to include the 65 mph roadways. Many of the sites were also changed, incorporating as many automated sites as possible.

Late 1995 the National Maximum Speed Limit was repealed and the submittance of speed monitoring data to the FHWA would be performed on a voluntary basis as determined by each state. In order to provide continuity in Minnesota's speed data, it was decided that the monitoring program would continue. Since there are no longer FHWA guidelines to be followed, the program has been modified to best fit Minnesota's needs. The roadway categories have been changed once again, as have the monitoring sites along with their numbering system. In the past, final data was adjusted using a theoretical error correction factor applicable to the federal statistical calculation for compliance scores. This is no longer done. Raw data is preliminarily screened for its validity and final calculations are based upon actual data without any correction factors.

Report Description

MONITORING SITES:

The map page gives a general description of the site locations around the state. The listing below gives the exact location of each site. There is a total of 32 automated speed monitoring stations that are scheduled to collect data each quarter.

The numbering system has been changed to make the sites easier to identify. Each site number includes the roadway type and district along with the Data Collection Site Number.

Example: 194037		1-9-4037
	1	Roadway Category
			Urban Freeway Rural Freeway Rural 2-lane/2-way Highway Rural Divided Highway (non-freeway) Urban Divided Highway (non-freeway)
	9	District that Site is in
	4037	Data Collection Site Number

SUMMARY REPORT:

The summary report classifies all the information by roadway category. Under each roadway classification is the number of sites that are located within that category. Each of these sites are scheduled to collect data for one 24-hour period during the quarter (this is also referred to as a session). Sites may be dropped each quarter due to invalid data or equipment failure. The number of sessions conducted and the number of vehicles collected are given to show the sample size.

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State of Minnesota
Department of Transportation
Speed Monitoring Station Locations

Map of Locations

SPEED
MONITORING
SITE No.

ROADWAY
R.P., & DIR.

COUNTY

LOCATION
DESCRIPTION

150346

190341

195076

230175

236901

240702

260227

264054

276250

290191

310057

310211

310219

310222

320209

320210

340225

360054

361085

370056

370622

373003

380199

390390

421023

430187

441028

450352

457090

460188

553013

590389