Bethel ME Percentage of
Overweight FHWA Type 10 Eastbound
2001
The JOHO image above is an example of the use of American
Image Inc.'s innovative visualization technique. Using JOHO,
you can make displays from your large traffic information bases. You can quickly
discern patterns and exceptions to the patterns, even in the large data sets
produced with vehicle sensors.
Please see the description of the <South Portland November image> for a
more detailed description of JOHO image concepts.
This image shows the percentage of eastbound FHWA Type 10 (6-axle) trailer
trucks passing the WIM sensor in Bethel, Maine that were overweight (exceeding
100,000 lbs) for every hour in 2001. JOHO computed the image by dividing
the count of overweight Type 10 trucks image by the total count of Type
10 trucks image and multiplying by 100. This is just one example of JOHO’s
computational functionality that can create images that explicitly show
information derived from the original data where it is impossible for the data
vendor’s software to provide such ad hoc functionality.
The image contains 8,760 data points. This is far more information than
traditional graphics programs can display.
Image Layout
The image has twelve panels, each showing one month in 2001, starting in the
upper left and ending in the lower right. As labeled on December’s panel, the
24 cells in the top row of a panel represent the hours in the first day of the
month. The bottom row of cells represents the last day of the month. The time
through each day is measured horizontally along each row, from the hour
beginning at midnight on the left to the hour beginning at 11 PM on the right.
Noon is halfway across the panel.
Each colored cell indicates the percentage of eastbound Type 10 trucks that
were overweight passing the sensor at that day during that hour. The legend at
the right indicates the relation between color and number of vehicles. The image
indicates percentages of fewer than 30% as the dark blue color at the bottom of
the legend. At about 50% the color changes from green to orange. The white at
the top of the legend indicates that 100% of the trucks were overweight during
that hour.
Image Interpretation
The most obvious pattern for these overloaded trucks is from 8 AM until about
7 PM on weekdays during the summer months, about 70% of the Type 10 trucks are
overweight.
The large percentage of eastbound overloaded trucks is due to the presence of
a paper mill east of the WIM site. Most of the overloaded trucks are probably
carrying loads of lumber.
The scattered white cells indicate that all of the Type 10 trucks in that
hour were overweight. This usually occurs in the nighttime hours when there were
only a few Type 10 trucks.
The Maine State Police, as the group responsible for enforcing weight limits
in Maine, are studying the use of these images is order to improve the
efficiency of their enforcement operations.
More Traffic Information
JOHO also provides various computational capabilities to manipulate
images created from initial data streams. Derived images generally get closer to
a “bottom line” that shows the analyst exactly the information that is most
useful. Because there are many
application specific manipulations that might be useful, the sensor vendor’s
software cannot provide the flexibility that is included in every JOHO
installation.
This site also contains FHWA Type 11 images and
total vehicle
count images that show other examples of how the Maine DOT is using JOHO
to monitor their sensors and to understand traffic patterns throughout the
state.
