August 11


Ignore Traffic Warrants at Your Own Risk

By Mike Spack

August 11, 2016

Political power, Signalized intersection, TIS, traffic studies, warrant analysis

A UPS distribution center was scheduled to break ground a few months after I started as the staff traffic engineer in Maple Grove, Minnesota.  The development project was through the environmental and city approval process before I started working for the city.  A traffic study was prepared for the project the year before by a credible engineering firm and the recommendations in the study were adopted as conditions of the development’s approval.

The traffic study recommended adding traffic signals at two intersections on the adjacent county road as part of the project’s mitigation plan.  The traffic signals were needed based on poor peak hour Levels of Service.

Hennepin County, Minnesota had (and still has) detailed standards for when a traffic signal is appropriate.  Those standards prioritize intersections that meet the eight hour warrants, not just the peak hour warrants.  When the developer and city submitted a permit application to install the two traffic signals, the county required the city to provide the eight hour warrant forecasts that weren’t done in the Traffic Impact Study.  Unfortunately, one of the two intersections that needed a signal for UPS was only forecast to be busy during the peak hours and wouldn’t meet the eight hour warrants.

We submitted the full traffic signal warrant analyses and Hennepin County denied our permit to install the traffic signal at the intersection that didn’t meet the eight hour warrants.  This put city staff in quite a bind.  The politicians were excited to have attracted this big employer to the city and UPS was on board for paying for all of the required improvements.  UPS thought they were good to go and had their contractors all lined up to meet their construction schedule.  Everyone was expecting the facility to be built and operating that Fall.

Because the signal warrant issue wasn’t identified during the approval process, this little sticking point was on the verge of derailing a multi-million dollar project.

The mayor ended up working with our area’s county commissioner to get a “variance” to the county’s traffic signal policy and that intersection is still signalized almost twenty years later.  It’s pretty common in the industry to call this situation meeting the “political warrant” that isn’t part of the official MUTCD.

The lesson here is that the traffic engineers need to do their homework when it comes to making recommendations.  Even if the analysis wasn’t done to address the county’s full policy, the traffic study should have identified that the policy existed and more study would be required.  Then city staff could have worked the process through before the city and state environmental approvals were granted based on implementing the recommendation plan.

Opening up the environmental/city process to address the signal would have delayed the overall construction project a year due to Minnesota’s abbreviated construction season.  Addressing the signal during the first run of the approval process wouldn’t have cost any time.

(Or the underlying lesson is that politics often trumps engineering if the project is big enough, which is something I often let my development clients know when they don’t like how the engineers are working out improvement plans.  Even though I don’t necessarily like it when developers try to go around our recommendations, property owners always have the right to try to exert political pressure in their favor.)

Visit Spack Academy and check out the Warrant Analysis Spreadsheets for sale there.

  • A project does necessarily have to big to have politics trump engineering. Unfortunately, too often things get done, or not done in some cases, because of political reasons related to all sorts of different projects, big or small. This has become more common in recent years and will probably only get worse since politicians are more concerned about fund raising and voter acceptance then engineering issues. Regrettably, when it comes to public works projects, quite a few people think that engineers are the guys standing around leaning on a shovel, don’t really know what the issues are since they “don’t live there”.

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    Mike Spack

    My mission is to help traffic engineers, transportation planners, and other transportation professionals improve our world.

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