|
~JuIY 1, 1994 TRAFFIC ,,~,,,,,,,~ ,,,,,, I
<br /> 9-5.00 (Continued) I
<br /> WARRANT 1: Limited Visibility A signal justification report need not be submitted I
<br /> for minor work done on a signal if the districts still
<br /> Where sight distance is limited, a flashing beacon considers the signal a justified installation. In
<br /> I
<br /> may be installed if the sight distance is less than general, work that changes the displays seen by
<br /> half kilometer (1/3 mile) on a rural high-speed drivers or changes the operation drivers are I
<br /> highway, or if the sight distance is less than that accustomed to requires an signal justification report.
<br /> ·
<br /> shown in the table for lower-speed highways. When in doubt, an signal justification report should
<br /> Locations qualifying under limited visibility must be submitted.
<br /> have previously had adequate warning signs and ' i
<br /> installed. The of a signal justification report is to
<br /> pavement
<br /> markings
<br /> purpose
<br /> I
<br /> document that an engineering study has been done
<br /> SPEED SIGHT DISTANCE SPEED SIGHT DISTANCE and that engineering iudgement has been used to
<br /> ~ LESS THAN (MPH} LES.S THAN demonstrate that a traffic signal installation is I
<br /> 50 310 meters 20 650 feet justified. To show that an analysis of the factors
<br /> I
<br /> 60 370 meters 25 800 feet contained in the warrants of the MN MUTCD has
<br /> 70 440 meters 30 975 feet been done, and to demonstrate that the installation
<br /> 80 560 meters . 35 1125 feet or improvement of a signal will improve the overall · I
<br /> 90 620 meters 40 12'/5 feet safety and/or operation of an intersection and be in
<br /> 100 650 meters 45 t450 feet the public's best interest.
<br /> 110 700 meters 50 1600 feet
<br /> This purpose can best be met when the report
<br /> WARRANT 2~ Accident Rate includes the following information:
<br /> I
<br /> . Intersection location: trunk highway cross- ·
<br /> A flashing beacon may be installed where: a high- street name and county road numbers,
<br /> I
<br /> hazard safety improvement criteria are met, as municipality county. A map should be
<br /> described elsewhere in the Manual or, in one year included which identifies the site.
<br /> there have been four or more accidents of the right- Type of work: type of signal or beacon I
<br /> angle or left-turn type, or of the type deemed proposed, whether temporary or permanent.
<br /> I
<br /> preventable by a flashing beacon. Character of site: function and importance of
<br /> roads, number of lanes, existing and
<br /> WARRANT 3: School Crossing proposed geometrics, channelization, I
<br /> I
<br /> A .flashing beacon may be installed at an
<br />
<br />t
<br />I
<br />l
<br />I
<br />l
<br />t
<br />
<br />established school crossing where, during the heavy
<br />crosswalk usage periods, there are more than 500
<br />vehicles per hour (actual or effective rate) crossing
<br />the crosswalk, AND. insufficient usable gaps for
<br />'pedestrians using the crosswalk.
<br />
<br />WARRANT 4: Rural Trunk Highway Junctions
<br />
<br />At or near some rural junctions of two or more
<br />highspeed trunk highways, a flashing beacon may
<br />be installed to warn drivers of an unexpected
<br />crossing of another highway.
<br />
<br />9-5. 03.03 THE SIGNAL JUSTIFICATION REPORT
<br />
<br />A signal justification report (See Figure 9.1) must be
<br />submitted for all new construction of signalized
<br />intersections, when a signal is completely rebuilt,
<br />when major work is done on a signal, or when a
<br />signal is upgraded preceding turnback to the local
<br />jurisdiction. The signal justification report may
<br />Incorporate the project memo (See Figure 9.1A)
<br />when the project is only to install or revise an
<br />existing signal. When the signal is part of a larger
<br />project, the signal justification report is separate
<br />document from the project memorandum, and only
<br />its cover sheet is ineluded with the project
<br />memorandum. The signal justification report should
<br />not be included in the project memo when the signal
<br />is only part of the project.
<br />
<br /> grades, presence or absence of parking, bus
<br /> stops and routes, posted speed limit, 85th
<br /> percentile speed if markedly different, sight
<br /> distance restrictions.
<br /> Land use: present land use at the
<br /> intersection, presence of any special traffic
<br /> generators, proposed or likely future
<br /> development.
<br />" Traffic control: existing traffic control, present
<br /> and planned adjacent signals, proposed or
<br /> existing coordinated systems.
<br /> Actual traffic volumes at an 'in place
<br /> intersection. Volumes must include at least
<br /> 18 hours of counts on all approaches,
<br /> turning movement counts for at least a.m.
<br /> and p.m. peak hours. Unusual numbers of
<br /> heavy vehicles and unusual percentages of
<br /> turning movements must be noted. Volumes
<br /> shall have been counted within two years of
<br /> the date of submission of the report.
<br /> Mn/DOT-generated or-approved volume
<br /> estimates for a proposed intersection, such
<br /> as found in an official TAM or SPAR report,
<br /> and for which warrant estimation methods
<br /> are acceptable.
<br /> P, edestrian counts, particularly if the
<br /> intersection is a school crossing or is used
<br /> by large numbers of elderly or handicapped
<br /> pedestrians.
<br />
<br /> I
<br /> I
<br /> I
<br />I'
<br />I
<br />I
<br />I
<br />
<br />I
<br />
<br />1012
<br />
<br />9-15
<br />
<br />I
<br />
<br />
<br />
|