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PRACTICE SUMMARY <br /> Mailboxes 0of 2) <br /> DESCRIPTION • PROVEN, OR EXPERIMENTAL <br /> Provide breakaway mailbox supports for new installations, as part of rehabilitation ■ The design has been PROVEN crashworthy. <br /> projects, and when new homes and businesses apply for entrance culverts. ■ From a crash perspective, using a breakaway mailbox design would be <br /> • OPERATIONS considered TRIED—no rigorous evaluations of the deployment were found <br /> in the literature. <br /> Installation of the swing-away design mailbox support has no effect on traffic <br /> TYPICAL CHARACTERISTICS OF CANDIDATE LOCATIONS --- <br /> operations. However, the swing-away design benefits snowplow operations by <br /> allowing more maneuverability of the snowplow with less chance of hitting the Examples of candidate mailbox replacement opportunities are shown below. Steel <br /> support and damaging the mailbox. tractor wheels, milk cans filled with concrete, chains, and massive I-beams are only <br /> TYPICAL a few of the devices used to support mailboxes. Agencies can develop a policy <br /> COSTS that replaces existing mailbox structures with the MnDOT Standard Swing-Away <br /> Implementation Costs = $100 to $200 per mailbox support design during reconstruction, resurfacing, or new access permitting processes. <br /> SAFETY CHARACTERISTICS <br /> A review of crash data for roadways in the State of Minnesota from 2001 to 2010 <br /> found an average of 85 crashes per year involving a mailbox support, with an <br /> average of 3 severe crashes per year. <br /> The MN MUTCD requires that all roadside sign supports in clear zones be <br /> breakaway, yielding or shielded by a barrier or crash cushion. State Statute 169.072 <br /> considers any mailbox not meeting breakaway requirements to be a road hazard <br /> and gives agencies the ability to remove non-conforming mailboxes. A review <br /> of rural roadways in northern Minnesota shows that there is an equal chance <br /> of a vehicle leaving the road to hit a mailbox as there is to hit a roadway sign. <br /> A preliminary review of the number of signs and the number of mailboxes was <br /> conducted on three roadways (Itasca CH 35,TH 6, and Itasca CH 3). Over a total of <br /> 16 miles, there were 134 traffic signs and 135 mailboxes.The density of mailboxes <br /> was equal to the density of roadway signs. Having crashworthy mailbox supports <br /> should be as high of a priority as having crashworthy signs supports. <br /> The MnDOT research has found that the swing-away mailbox assembly meets the Examples of Unacceptable Installations <br /> requirements of the AASHTO Manual for Assessing Safety Hardware for breakaway <br /> support structure. <br /> �HNESp'' <br /> 2 <br /> �9 <br /> �t�® �mhlOi T0.P ZO <br /> MINNESOTA'S BEST PRACTICES AND POLICIES FOR SAFETY STRATEGIES ON HIGHWAYS AND LOCAL ROADS / SEPTEMBER 201 1 <br />