PicoCount 2500 Traffic Counter Manual
VehicleCounts.com
www.vehiclecounts.com
Last Updated 11/11/2009
This manual is available in full color PDF format at this manual download.
This section runs you through a study using the PicoCount 2500 counter and the TrafficViewer Pro software to familiarize you with both the hardware and the software.
When you receive your PicoCount 2500 check it closely for damage.
You should have received the following items:
+ The PicoCount Counter.
+ A Quick start manual.
If you are using the USB download cable, make sure it is connected before starting TrafficViewer Pro software. The TrafficViewer Pro software scans for all Windows® serial port connections (including USB) as it starts, if a new Windows® serial connection is made after the software is running, the software will not be aware of the serial connection.
Upon starting TrafficViewer Pro software, you should see the following window, which we call the TrafficViewer Pro desktop:
Occasionally, you might see the screen below pop up first, if so, just click on "Close" when it has finished (discussed in detail later in this manual).
Connect your PicoCount 2500 to your PC with the download cable. Then click on "Auto-Detect" in the Communications dialog box:
After a few seconds the communications dialog box should show the PicoCount connection status similar to below:
Once this screen appears, you need to reset the counter by clicking on the "Reset Unit" button in the lower left of the TrafficViewer Pro screen.
The following dialog will pop-up:
Click on "Yes".
Reseting the counter insures that any current data in the machine is discarded and most importantly that the date/time is synchronized with your PC. As a practice, you should always reset the counter, before setting it out for counts. This insures that you only have one study and it keeps the PicoCount 2500's built-in clock "synchronized" with your PC.
You are now ready to set the PicoCount 2500 out for counting. The PicoCount 2500 has no power switches and is ALWAYS counting, though no memory gets used if there are no "hits" on the air switches.
For your first count study with this counter, we recommend doing a test study so that you become familiar with setup and data collection, before just going off and doing a critical study.
You set the PicoCount 2500 out like any other automated traffic counter (ATC). If you are new to using counters with air hoses, you should read the "Setting up the air hoses" section of the manual first.
If you want speed and classification, use both hoses placed parallel across the lane and at your default spacing (which can be anything from 1 foot to 16 feet, or 30cm to 5 meters). If you don't have a preferred spacing, 3ft or 1 meter are good options.
If you are only want axle counts (or vehicle counts), you may position the hoses any way you like (side by side, split median, long-hose/short-hose, etc.).
Once the hoses are set, connect them to the PicoCount 2500. There are two hose connections to the PicoCount 2500, the "A" hose connection and the "B" hose connection. The "A" hose connection is the nozzle (barb) closest to the letter "A" embossed into the PicoCount 2500.
This begins your test study.
If you have purchased a CountBuddy, you may plug it into the data connector at this time. It's red and green LEDs will blink momentarily letting you know it is powered up okay. As vehicles pass over the hoses, the CountBuddy LEDs will blink each time a hose hit is recorded, green for the "A" hose and red for the "B" hose.
Once you have collected your test study, connect the PicoCount 2500 to your PC as described above, and you should see a screen like this:
Now click on the "Download" button in the lower left of the TrafficViewer Pro window, and you will see a screen like this:
First the Downloading dialog will pop up showing a progress bar of the download and when it is complete it will appear as shown above. Immediately after the download is complete the Data Setup dialog will appear as shown above.
If you are classifying or collecting speeds, you will need to specify the spacing you used on the hoses. The default is 36 inches, so change to the spacing you used in collecting the data. Note that the default spacing can be changed in "Preferences". See the section in the manual on "Preferences". Mark the hose setup that best represents how you had the hoses set up for the study, and select the direction the traffic was moving.
If you were just collecting volume only data mark the check box "Spacing unknown or Axle hits Only". Then mark the hose arrangement that best represents how you had the hoses set up.
The top three fields are optional.
Once you are satisfied with the settings, click on the "Continue" button and a "Data Overview" screen will appear which has a thumbnail summary of the data you just collected.
At this point it is wise to click on the "Save Data" button to save a RAW data file with your Header settings. You should ALWAYS do this, even though you may not think you will need the RAW data again (its called hedging your bets against Murphy's Law).
This panel shows some additional statistics concerning the data collected, and on the bottom of the panel are two action buttons, one will give you a graphical representation of the data and the other will give you a readable list of the data points.
Clicking on the Timestamp Graph will pop up the following panel:
This is a very complex panel with many details. You just need to play around with it to get the hang of how everything works. This is a brief description of the panel features.
The central white area is the graphical representation of the A and B hose hits. In this area the hose hits are represented by black dots if the data point is being used or red dots if the data point is not being used (has been filtered out). The Green bar above the hose hit dots spans all of the dots used in defining a vehicle. Above these bars are details of the vehicle classification and speed. You can zoom in and out by selecting the Milliseconds per pixel pull-down list in the upper right of the panel. Once you have selected the Milliseconds per pixel, if you have a scroll wheel on your mouse, it will take over zooming in and out. The white graphical area will display one day of data at a time, the day being shown is indicated in the upper left of the panel by Current day. If the study goes over 1 day in length, the >>Prev Day and Next Day >> buttons at the bottom of the panel will activate appropriately.
Just below the graphical data scroll bar is a time box in black which indicates the time in (hh:mm:ss.mmm) at the center line of the white area.
To the right of this is a field called Sync Times which is very useful for synchronizing the timestamps to a video of the same traffic. This is done by positioning the vehicle being used for synchronization on the center line of the graphical display, then advancing the video until the same vehicle is centered in the video display. At this point you enter the video display time into the sync times field, then click on the Sync Times button. Now the time box in black will reflect the time on the video tape as you pan around the data.
To the right of the white area there is a list of the timestamps for all the axles currently showing on the graphical display. If you do not want this list, you can uncheck the checkbox directly above the list. The graphical view will then expand to fill the whole area. Also, you can view the timestamp list in several formats.
Above the white graphical area are a couple of sections that let you calculate distances between axle hits and speeds by using an A to B or B to A set of timestamps, or to calculate the time difference between any two timestamps.
To calculate time difference, position your mouse over the first timestamp dot of interest and click on the left mouse button. Next move the mouse over the timestamp dot you are trying to calculate the time difference to and click on the right mouse button. the results of the difference will show in the Difference field.
You do not have to have the mouse perfectly centered, just near the dot and it will lock onto that dot (a pop-up box will give the timestamp info about the dot when you are in the correct spot). A similar behavior will occur if you hover over the green bar representing the vehicle with your mouse, a pop-up box will give you more details about the vehicle, including axle spacings.
To calculate distances, you first need to calculate the speed of the vehicle. To calculate speed, select the Calculate Speed checkbox, then position the mouse over the leading axle A or B (dot furthest to the left) and click on it with the left mouse button. Then move to the matching A or B dot and click the left mouse button again. You will see the speed in the Speed field. Once speed has been determined, you can calculate distances. To calculate distance, select the Calculate Distance checkbox, then position the mouse over the first dot of the two you want to figure distance between. Click the left mouse button, then move to the second dot and click the right mouse button. You will now see the distance in cm or inches between the to dots in the field Distance.
This section describes how to customize how TrafficViewer Pro classifies vehicles. As shipped, TrafficViewer Pro has several default classification schemes, such as, FHWA and Austroads. These are industry standard schemes that follow government generated descriptions of vehicle classifications. Since counters like the PicoCount 2500 measure axle hits on pneumatic hoses, the classifications schemes have been developed on appropriate axle spacings. Normally, the default schemes are all you should need for most counting applications. However, some organizations may want a classification scheme that does not follow the default schemes, or have special schemes for special count studies.
When you click on the Advanced menu item in the main menu you will see:
Then when you click on Edit Classification Rules/Schemes you will see a panel like this:
This panel will allow you to edit or create a new classification scheme. With this panel you can build up classification rules based on a variety of characteristics of the data. We will describe what each of the pieces to generating a classification scheme are and how you can go about it. Be warned, this is a section for advanced users that have a thorough knowledge of vehicle characteristics and vehicle classifications.
First though, a little information on how TrafficViewer Pro processes the raw timestamped data in a multi-pass method. The first pass through the data TrafficViewer Pro filters the data based on the hose configuration specified in the header screen. In the case of two hose setups that would allow speeds and classifications, axles in the two channels are "matched", separating forward and reverse traveling vehicles into seperate "tracks". Next, the data is scanned for the presence of air pulse "echoes" in the data and if detected, these "echoes" are filtered out. If the header indicates a "volume only" configuration, then the data requires no further processing, otherwise, the next pass would utilize the data in the Classification Scheme to attempt to classify and count vehicles.
In this pass TrafficViewer Pro begins at the start of the data and generates a "cluster" of axle hits. A cluster starts with the first axle hit and continues until the Max Axle Spacing (field in the middle of the panel above) is exceeded. Note that distances can be specified in either Inches or Centimeters (You determine this in the upper right side of the panel in the Display/Enter in field).
Once the cluster is built, then the data is applied to the classification rules indicated in the large white field in the lower left side of the panel. Rules are processed sequentially from top to bottom. If all axles in a "cluster" match one of the rules, the vehicle is classified accordingly and TrafficViewer Pro then fetches the next "cluster" from the data file. If a cluster fails to process to a classification, the cluster is then is further processed according to specified options (see the Unclassified Handling tab below).
The recommended option is to re-cluster the failing cluster. A cluster is "re-clustered" by removing a pair of axle hits and running the new cluster through the classification rules. If this fails, it will continue removing single axles until the cluster is too small (less than two axles) or a successful classification has been established, at which point the removed axle hits are now re-processed until all hits in the original cluster have been resolved, or optionally discarded.
A good example of how this "re-clustering" would work would be to consider three cars "tail-gating". The original "cluster" would grab 6 axles. First pass through the rules would fail to match any 6 axle vehicle to that particular array of axle spacings, therefore, we would drop the last two axles off and re-process with 4 axles. Again, no 4 axle vehicle would classify with those axle spacings, so we would drop 1 more axle. The remaining 3 axles again fail to classify in this example, so we would drop 1 more axle. The remaining two axles would classify as a "car", so we now try processing the remaining 4 axles. Again no 4 axle vehicle would classify with the remaining axle spacing, so we drop 2 axles. When reprocessed, we would classify the two axles as a "car". Then we grab the remaining 2 axles and process them which would also classify as a "car". As a result, the original cluster would resolve as 3 cars.
Now lets analyze the Classification Rules panel in detail. The panel can be broken into three main sections, the upper part (or scheme management section), the middle part (or rules management section), and the lower part (scheme saving). Starting with the top part of the panel:
Display/Enter in: In this field, you select spacing information in centimeters or inches when viewing and editing the scheme rules. You can change this at any time during the viewing or editing of the scheme rules.
The middle part of the Classification Rules panel allows you to view and change the rules for the scheme highlighted in the scheme list in the upper part of the panel. This section of the panel will appear like below for the AustRoads scheme selected in the upper panel:
Now we tackle the editing rules. All rules are tested sequentially from the top of the rules list to the bottom. When a rule yields a classification, the testing is finished and we move to the next cluster to classify. When a rule fails, by default, it will move to the next rule. The rules are all structured as an "If...Then..." type of sequence.
The big white rules box contains the rules descriptions. If a rule has a "+" inside a box in front of it, there are hidden sub-rules. Clicking on the "+" box will make the sub-rules visible (expand them). This also applies to sub-rules that may have sub-rules.
Now it is time to describe how to create/edit a rule. We will start with the default FHWA as an example. First, we highlight the first rule as such:
Notice that when a rule is highlighted, the fields on the right side of the panel are the details of the rule. We will now do a brief description of each button and field on this section of the panel, they will be discussed in more detail later as we start editing.
Expand All. This button will expand all the rules and sub-rules in the rules box. This would be good for an overview of all your rules to make sure there are no conflicts, or missing rules, or mis- located rules.
Collapse All. This button will collapse all expanded rules and sub-rules to the minimum (shown in panel above), this is the default form of the rules box when you first open it.
Refresh. This button refreshes the data showing in the rules box.
New Rule. This button will insert a new blank rule into your rules list. It will be inserted immediately below any highlighted rule and at the same level as the highlighted rule.
New Sub-Rule. This button will insert a new blank sub-rule for the highlighted rule. If there are already sub-rules, this new rule will be inserted at the bottom of the existing sub-rules.
Delete Rule. This button will delete the highlighted rule or sub-rule and any sub-rules below it.
ELSE. This checkbox will insert the keyword "otherwise" in place of the keyword "if" in the rule.
Invert Test. This checkbox will essentially invert the test parameters by inserting the keyword "not" in front of the test parameters.
Test Type: This is a pull-down list of the types of parameters that you may use in defining your rule, such as Num Axles (Number of Axles), Axle Spacing, etc.
Min: This field is the minimum value in a two parameter test, or the only value in a single parameter test.
Max: This field is the maximum value in a two parameter test and is not used in a single parameter test.
Result: This is a pull-down list of what of what is to be the result of a successful rule test. You can specify to Continue Testing, Classify, Not a Vehicle, or Stop the Rule.
Up. This button will cause the highlighted rule in the rules box to move up one position in the list.
Down. This button will cause the highlighted rule to move down one position in the list.
Left. This button will cause the highlighted sub-rule to move one indent to the left.
Right. This button will cause the highlighted rule or sub-rule to move one indent to the right.
Duplicate Rule. This button will create a duplicate of the highlighted rule, placing it directly below the highlighted rule.
Duplicate Sub-rules too. This checkbox will cause a highlighted rule being duplicated to also include all the sub-rules of the highlighted rule when the Duplicate Rule button is clicked.
The rules in the rule box are organized in a tree like structure, with the main rules justified against the left margin (or side of box). The sub-rules are then indented to the right, and sub-rules of sub-rules are indented further to the right. You can see these sub-rules for a rule or sub-rule by clicking on the "+" symbol in the box which will "expand" the rule:
As you can see, the sub-rules for the first rule are indented to the right. As mentioned before, as the tests proceed, each sub-rule is tested sequentially from top the bottom until a match is made or all tests are exhaused, in which case, the rule does not apply and the next rule down the list is tested against the cluster.
Now, let us go through the steps of creating a new scheme, so first thing is to click on the New button at the top of the panel:
Then click on the Classifications tab in the middle of the panel:
Now, let us define some classes of vehicles. For this example, we will create three classes of vehicles as such:
For this example, leisure vehicles would be motorcycles, cars, pickups, SUVs, etc. Commercial vehicles would be large vans, delivery trucks, buses, and motorhomes. Heavy trucks would be Dump Trucks and Tractor-Trailer Semis of all types. The Truck? checkbox is usually used to indicate trucks that are per-axle load restricted and regulated, so special statistics for these show up in the reports.
Now let us return to the Classification Rules tab. We first need to enter values for Max Axle Spacing and Group Axle Spacing and then click on the New Rule button. Let us Display/Enter in: Inches, so the panel would look something like this:
Note, we used the spacings from the default FHWA scheme to fill in the Max Axle and Group Axle fields for this example.
Now we need to fill in the first rule. First select the Test Type from the pulldown list.
The list has the following rule test types available:
Always. This test type involves no parameters and will always be true. It may be placed at the end of a list of tests to force a result if all of the prior rule tests fail.
Axle Spacing. This test type is on axle spacing. If you choose this, you will need to enter the axle pair that the test is to be run on, and a minimum and maximum spacing to pass the rule. Note, that the number of axle pairs is always one less that the total number of axles in a cluster: Axle 1 to axle 2 spacing is axle pair 1, axle 2 to axle 3 spacing is axle pair 2, etc.
Group Spacing. This test type is on group spacing. It is similar to axle spacing, but only on the groups, rather than on individual axles (unless of course there is only one axle in the group). As discussed previously, groups are formed by axles that are equal to or closer together than the Group Axle Spacing parameter. The group spacing is considered to be from the last axle in the first group of a group pair to the first axle of the second group (in other words, the length of the gap between groups).
Num Axles. This test type is for the number of axles in the cluster.
Num Axles in a Group. This test type is on the number of axles in a particular group.
Num Groups. This test type is for the number of groups in the cluster.
Spacing from First. This test type is the spacing from the first axle to a specified axle.
Total Axle Spacing. This test type axle spacing from the first to the last axle in a cluster (roughly equivalent to total vehicle length).
Let us set the first rule for all clusters with only two axles. So highlight the first (and only) rule and select the Num Axles for the test type. Next fill in 2 for the Min: field (note that Max will automatically fill with 2 also). Then select a result of a successful match:
In this case, we need to do further testing to see what class the vehicle might be, so we will choose Continue Testing. The other options Not a Vehicle would only be chosen if all prior tests had failed and you did not want any subsequent testing to be run on the cluster data (in other words you wish to force re-clustering). Stop this Rule would be chosen if you did not want any further tests at this sub-rule level to be executed.
Since two axle vehicles could fall into more than one class (leisure vehicles, or commercial vehicles in our example), we need to do further testing, so we will need to add a New Sub-Rule, so we will click on the New Sub-Rule button.
Let us say any vehicle with an axle spacing of 36 to 142 inches will be considered a class 1 vehicle (leisure vehicle), and vehicles with an axle spacing of 142 to 455 inches will be considered a class 2 vehicle (commercial truck or bus). So we set up this Sub-Rule by selecting Axle Spacing as the Test Type, a Target value of 1 for axle pair 1, a Min of 36 inches and a Max of 142 inches, a result of Classify as Class 1.
Now with our just created rule highlighted, click on the New Rule button which will give us a new rule at the same level as the highlighted rule.
So now highlight the new sub-rule and fill in as Axle Spacing, Target 1, Min 142, Max 455, Result - Classify as class 2.
This finishes our first rule which is for 2 axle vehicles which classify as class 1 or class 2. However, class 1 and class 2 vehicles could also be towing trailers which need to be accounted for and may add one or more axles. For this classification scheme we assume that no class 1 or class 2 vehicle will have a dual axle on the rear, all multi-axle tandem axles will be on heavy trucks only (class 3 vehicles), but a trailer towed by a class 1 or class 2 vehicle could have a tandem axle arrangement. A way to set up a rule for this is to look for vehicles that have 3 groups (front axle, rear axle and trailer axle(s)), but only have axle pair 1 spacings of a class 1 or class 2 vehicle. Therefore, we highlight our first rule and click on the New Rule button to set up a new rule.
Highlight the new rule, select Test Type as Num Groups, set Min to 3 (and Max to 3) and the Result to Continue Testing.
Next click on the New Sub-Rule button. Then edit the parameters as: Test Type of Num Axles in Group, Target to 2 (second axle/group), Min to 1 (we only want the second group to be a single axle), and Result to Continue Testing. With this sub-rule still highlighted click on New Sub-Rule.
We now use the same axle spacing rules on the first axle pair as previously to differentiate the classes.
By now we have rules to catch all instances of class 1 and class 2 vehicles, but not every cluster that fails to fall into either of those two classes is necessarily a class 3 vehicle, so we need to make sure that the cluster is a Heavy Truck. We can determine this by checking the axle pair 1 axle spacings. Therefore, we will make a new and final rule (for this example). Highlight the last main rule and click on New Rule, then highlight the new rule, set Test Type to Axle Spacing, Target as 1, Min 142 and Max 455, Result - Classify as 3.
This is a quick study on how you would go about generating a new scheme. Actual schemes can be considerably more complicated to cover all possible variations of vehicle types. There is one more section, the "Unclassified Handling" which is discussed in detail below. Namely, if the cluster does not pass any of the rules then what happens to the cluster data must be defined. Once you are satisfied with your new Classification scheme, you may save it by clicking on the Save Scheme button at the bottom of the panel. If you have a data file open already, you will see the data overview re-calculate showing the new results immediately. Also note that as soon as you save the scheme, the rules box collapses all the rules automatically to keep things more readable. If you need to edit or review the details, you can expand each rule, or click on Expand All.
This tab allows you to dictate what to do when a cluster of axles has failed to be classified. This panel is organized into two areas; the upper area gives you five choices of what you may want to do, and the lower area contains the tests for your choice. We will discuss each of these options in more detail.
Do nothing. Leave cluster unclassifed/unhandled.
This option is pretty self-explanatory. The unclassified cluster of axle hits is just thrown away. This option might be most useful in very clean data where there are occasional bogus hits due to non-vehicular traffic such as bicycles, construction equipment, foot traffic, etc.
Attempt to re-cluster if...
This option is the recommended option for handling a cluster that fails to classify. The tests here dictate how the re-clustering is accomplished. By default re-clustering will occur if the unclassified cluster has more than 3 axles (or 3 axles if the Only allow a re-cluster if ALL.... checkbox is unchecked). However, you can modify this rule and others by activating various tests.
# of axles is greater than. This test if selected will allow you to limit re-clustering to clusters that have more than the specified axles.
# of axle groups is greater than. This test if selected will allow you to limit re-clustering to clusters that have more than the specified groups.
Cluster length is greater than. This test if selected will allow you to limit re-clustering to clusters that represent more than the specified total length (distance from first axle in the cluster to the last axle in the cluster).
As mentioned in the panel descriptive text, any one or all of these limiting tests can be selected. If multiple tests are specified, they are effectively OR'ed together. For instance in really heavy traffic, you may want to specify that the cluster length cause a re-clustering.
Only allow a re-cluster if ALL... This checkbox will only allow re-clustering if ALL of the axles in the cluster eventually get used in classifying vehicles. For light to medium traffic this is a good option, it maximizes accuracy. However, in heavy traffic, you may find that unchecking this box gives better results.
After attempting to re-cluster, if... This pull-down list gives you several options on what to do with the cluster if it fails to re-cluster. These are the same options that we have if we chose not to re-cluster in the first place.
After you have selected what you want to happen to the failed re-clustering data, click on Configure to display and edit the test panel for that option (same as the test panels for those options discussed above and below this option, except for the appearance of a <<<Back button which allows you to return to this test panel after setting the tests). This insures that data that fails re-clustering still gets handled in a meaningful way.
Always classify as...
As stated in the panel description, this option would allow you to place the unclassified cluster (or partial cluster if this was the final result of the attempt to re-cluster) into a special class for unclassified vehicles. Alternatively, if the traffic is primarily cars and small pickups and SUVs, you could treat any unclassified cluster as 2 vehicles, such as 2 class to vehicles, assuming the cluster was probably due to interfering vehicles.
Divide unclassified axles by a specified value and put into a specified class...
Again the description on the panel explains pretty clearly how this option works. This option is similar to the Always classify as... option, except, if you know the statistical makeup of the vehicles in the study, you could make a reasonable estimate of the makeup of the unclassified cluster in partial axle counts and reduce it to a single class.
Use a table to decide classes using percentages...
This option can be used to classify unclassified clusters effectively when you have statistical knowledge about the traffic make-up (the average the vehicle distribution by class). This would be most useful in very heavy congested studies when the normal methods are resulting in a significant number of incorrect classes or unclassified vehicles. It would not be appropriate in studies where you have no reasonable knowledge of the traffic make-up.
As shown, you can have unclassified vehicles be classed according to a distribution table. The "%" column indicates what percent of the unclassified clusters will be assigned to that class. The percentages in the "%" column must add up to 100%. For instance, if a cluster fails to classify, then this option will assign the cluster to a class based on the percentage of likelyhood it is a particular class. For instance, according to the above settings, if there were 100 unclassified clusters in the data file, 50 of them would be classed as class 2, etc.
In addition to just a simple percent distribution, you can also add tests for the number of axles, and/or the total cluster length (from first axle to last axle in the cluster), for each classification, to further refine correct distribution of the probabilities. If you wish to use either or both of these tests, just check the appropriate checkbox. When you do this additional columns will show up in the table to allow you to set minimum and maximum parameters for axle counts and total length. For example with both tests checked, the table will expand and would look something like this:
At the bottom of the Classification Rules panel is a Save Scheme button. When this button is clicked, any and all changes made to the highlighted scheme in the schemes list will be saved to that scheme. Note! If you modify one of the default schemes and save it, it will now show with a (*) symbol following it. Your modified version will now take precedence over the default scheme. If you should later delete or rename this scheme, the original default scheme will once again become active.
The one of the most important factors in getting good counts with air hose counters is in proper setting of the hoses, so that is where we start, but first a little education.
Air hose comes in a variety of sizes, shapes and materials. For traffic counting though there are only a few to consider.
Choosing a material:
All air hose used in traffic counting is made of natural rubber or a synthetic rubber referred to as EPDM.
Natural rubber is softer than EPDM rubber for a given thickness and hole size. Therefore, natural rubber is slightly easier to handle and store.
Natural rubber can be degraded by exposure to UV from sunlight, whereas EPDM has been formulated to be resistant to UV degradation.
For hot temperatures, EPDM is the preferred rubber, and for cold temperatures natural rubber is the preferred rubber. EPDM is the most popular rubber used because it performs well over a wide temperature range from hot desert conditions down to near freezing whereas natural rubber performs best from warm temperatures down to well below freezing.
For a given hose size and length, signal attenuation in natural rubber is slightly higher than EPDM, which means that EPDM is better for long hose runs.
In the USA, natural rubber is mainly considered a "winter" hose, and is mainly used in the northern latitudes.
Choosing a size and shape:
There are currenly three shapes of hose in use today; round, half-round, and dual-hose.
Round is by far the most popular and easiest to use. It is suitable for the majority of counting applications. There currently are two sizes which are most common, normal hose and mini hose.
Normal hose is about 15mm outside diameter (9/16 inch or 0.600 inch). It comes with either a 6.3mm hole (1/4 inch or 0.250 inch), or a 4.8mm hole (3/16 inch or 0.188 inch).
Mini hose is about 9.3mm outside diameter (3/8 inch or 0.365 inch). It comes with a 4.8mm hole (3/16 inch or 0.188 inch). The profiles of these three styles are summarized below:
The normal hose with the 6.3mm hole is probably the most common hose in use. It has good resistance to wear and generates healthy air pulses. It is the preferred hose in very long hose runs.
The normal hose with the 4.8mm hole is stronger, stiffer and heavier. It is intended for very heavy traffic conditions, or where there is a lot of truck traffic. It also would be the hose of choice for unimproved and gravel roads. The air pulse it generates is weaker than the hose above, so longer runs are not practical.
The mini hose is fairly recent as an air hose, but is becoming very popular. It generates a smaller air pulse than the normal hose with the larger hole, so it is not suitable for long hose runs. It's biggest appeal is that it is quite a bit lighter and more pliable than the normal hose. If you are setting out lots of counters each day, it can save a lot of labor.
The mini hose does not hold up as well to traffic wear as the normal hose. As a rule of thumb, in a very busy count program, normal hose will usually last a full count season (in most areas a count season goes from spring through fall) before needing replacement. Mini hose on the other hand may only last half a season before needing replacement.
Half-round, because of its beefier build, finds use in very heavy traffic, where there is a lot of heavy truck traffic, or where the hoses are going to be left out for extended count times. This hose is trickier to lay down on the road, the flat side must always face the roadway, and it is pretty difficult to handle.
Dual-Hose is relatively new. It is generally constructed of two mini hoses with a webbing in between that maintains the hoses at a fixed, close, spacing. This hose must be mounted to the roadway with it's flat side against the pavement. It is more complex to attach to the roadway, and harder to handle, but is a much more reliable way to place down two hoses at one time. This hose can only be used, for speed and classifying, with the newest generation of traffic counters that have the time resolution to give satisfactory results.
This section describes the various methods used to attach the hose to and near the roadway. Proper attachment of the hose is very important to getting proper counts.
Methods of Attachment:
There are a variety of methods used to attach hoses to the roadway and shoulders. We will discuss each of these methods along with their pros and cons. Attaching a hose involves two distinct operations, placing an anchor and gripping the hose.
Anchors:
An anchor is the device attached to the roadway or shoulder that the hose will be attached to.
There are several devices used for anchors. Choice of the anchor device will depend on several factors, like roadway surface material, shoulder surface material, roadway temperature, etc.
To determine the appropriate anchor device, you need to decide where the anchor points will be placed. When stringing hoses on roadways, ideally the anchoring is off the roadway surface, on the shoulders, however, this often not possible. Generally, the traffic counter unit will be mounted next to the roadway and the hoses will be strung across one, two, or more lanes of roadway. The end nearest the counter on most roadways can easily be anchored in the shoulder, except when they are cement sidewalks, or the shoulders are extremely soft, or non-existent. The far end of the hose must often be anchored in the middle of the roadway, depending on the hose configuration for the study you will be doing.
Choice of the anchoring device depends on the materials it must be mounted to. For shoulder anchoring, the materials will generally be compacted gravel and soil, or tarmac. For roadway anchoring, the materials will be tarmac or cement. Tarmac is easier to drive nails into when it is warmer whereas cement doesn't care about temperature, it is always hard.
The most common anchoring device is the nail. For tarmac roadways you would use tarmac nails, masonry nails, or PK nails. For soft shoulders you would use spikes which come in a variety of lengths from 150mm (6 inches) to 300mm (12 inches) depending on the firmness of the shoulder. You will need a pretty hefty hammer for driving in the nails or spikes. In tarmac, you can also use power nails and an anchor plate with a portable nail gun (not common, but quick).
Another form of anchoring device is the masonry screw. This would be mostly used in sites that are re-visited quite often, such as on-ramps to freeways, etc. This involves drilling a hole then hammering the screw anchor into the hole.
In tarmac in warmer climates you can directly screw into the tarmac with the proper screw and power screwdriver.
Anchoring in tarmac depends on the weather. When it is hot, the tarmac is soft and the anchoring devices must be longer to stay put. Sometimes it may be necessary to also use an anchoring plate held down by several nails. When it is cold, the tarmac can become very hard and shorter anchoring devices would be used.
Grips
A grip is the device used to attach the hose to an anchor. There are a variety of methods used for this purpose and we will discuss the pros and cons of each here. A hose has two ends, one end is terminated in the traffic counter and the other end is at the far end of the roadway or lane being measured. The grip at the roadway shoulder must attach to the hose in such a way that the hose is not pinched shut, yet it must hold the hose firmly enough that it will not slip. The grip at the far end of the hose (from the counter) simply has to hold the hose from coming loose from the anchor. We are going to discuss five different types of grips: Chinese fingers, figure-8, C-clamps, anchor-plate clamps, Nylon belt, and Nylon cord.
Chinese fingers are made from stainless steel wire formed into a patented web pattern that grips the hose in such a way that it will not pinch shut, and it will not slip. This is great for the counter end of the hose. These devices can also be very quickly attached to the hose and allow simple tension adjustment. In heavy traffic situations where you do not want to be out in the roadway any longer than possible, these devices can be a life saver. These are the highest cost grips we will discuss. In very hot climates, the rubber hose can get so soft that these types of grips can actually sever the hose since they are made from a narrow gauge stainless steel wire. You must get the correct size of grip for the hose thickness you will be anchoring. This type of grip can be attached to the anchor in two ways: You can pre-install the anchor and simply loop the anchor end of the grip over the nail-head. Once under tension, this grip will not normally pop off. The other method would be to use a large washer and drive the anchor nail through the washer and the anchor loop of the grip. This later method may be necessary in high speed traffic. However proper usage of road tape can solve the hose bouncing issue.
Figure-8 grips are made from a thicker gauge of stainless steel formed into a loop that is pinched near one end (looking like an unbalanced figure 8). These grips are easy to attach to the hose and adjust. They grip over a wide enough area that they normally will not pinch the hose shut. They also will hold without slipping once the hose is under tension. If the hose is bouncing a lot in traffic, slippage may occur. Appropriate application of road tape (discussed below) can prevent this. This type of grip can be attached to the anchor in two ways: You can pre-install the anchor and simply loop the anchor end of the grip over the nail-head. Once under tension, this grip will not normally pop off. The other method would be to use a large washer and drive the anchor nail through the washer and the anchor loop of the grip. This later method may be necessary in high speed traffic. For the hose end grip, you can apply some duct-tape over the grip, after it has been attached and the hose is tensioned, to prevent slippage. This type of grip is of moderate cost. This can also cut into the hose in hot temperature.
The C-clamp grip is good for the far end of the hose when it must be attached in the middle of a roadway. These grips are made of galvanized steel. This type of grip is first attached to the hose, then an anchor nail is driven through one or both of its mounting holes. You would use two holes in warmer climates when the tarmac is getting softer. This type of grip can pinch the hose shut so would not be considered for the shoulder grip. Since the anchor is installed through this grip, you must spend more time in the roadway installing it, especially if you have to drive in two anchors. This grip is of moderate cost.
The anchor plate is used for the far end of the hose when it must be mounted in the middle of the roadway and the tarmac is very soft from hot temperatures. Anchor plates are made of a thick gauge of galvanized steel and have 4 mounting holes. You can spend considerable time in the roadway installing this type of grip, particularly if you are using all of the mounting holes. Anchor plate grips pinch the hose shut. You must specify the hose size when purchasing the anchor plate. If the anchor plate grip ever comes loose, you have a fairly good size chunk of metal loose in the roadway which could cause damage to vehicles. The anchor plate grip is moderate to high cost.
The Nylon belt grip is made by cutting off a 10 to 15 cm ( 4 to 6 inch) length of the belt, folding it around the hose and driving a nail through it into the roadway. It is only useful as a grip at the far end of the hose. It cannot prevent slippage, therefore the end of the hose has to be large enough not to slip through the grip, this is usually accomplished by tying the end of the hose into a knot (see end-plugging the hose below). This can be a low cost grip, but you have to buy a roll of the belt and cut it into grips.
Grips made of Nylon cord are very popular, namely because they are cheap. You cut off a strip of cord and literally tie the hose to the anchor. Once you get the hang of tying proper knots to prevent pinching the hose, these type of grips can be as effective as the figure-8 types of grips. This type of grip has a real advantage in very hot weather, because the Nylon is relatively soft and flattens out under tension, it will not cut into the rubber as it gets soft. This type of grip is the least expensive, but does require proper knot tying to not have problems. For the hose end grip, it is a good idea to apply some duct-tape over the knots after they have been attached and the hose is tensioned to prevent slippage.
To prevent moisture, dirt, and grit from entering the hose, the far end needs to be plugged. Moisture in the hose can block the airway, whereas dirt and grit inside the hose can cause rapid breakdown of the hose, by lacerating the inside surface when vehicles compress the hose as they are driving over it. Dirt, grit, and hose particles can eventually get vibrated all the way down to the air switches and cause the air switches to become clogged and non-functional. One exception to plugging the end of the hose is in very hot temperatures, particularly when the day to night temperature extremes are large. In this case, a very small pinhole in the end-plug is recommended to keep the air pressure inside the hose normalized. We will discuss a variety of methods to plug the end of the hose.
Tying a knot at the end of the hose. For the mini hose this is very easy to do. Depending on the stiffness of the normal hose being used, this may or may not be an option. It is a common method used. The big knot makes using C-clamps or Nylon belt grips easy, since it will not slip through them. If the hose is terminated in the middle of the roadway, the big knot might be objectionable. In very hot conditions, the knot would not accomodate a breather hole.
Hex-head bolts made of galvanized steel, stainless steel, or Nylon, which you can pick up at local hardware store, can make a good end-plug. You have to choose the proper size thread for the center hole of the hose. The hex-head makes it easy to get leverage when threading the bolt into the hose. If you are needing breather holes, this scheme will not work. These are low cost.
Commercial brass end-plugs. These devices are barbed and just press into the end of the hose. You have to specify what size center hole they are designed for. These can be purchased with a pin-hole for hot temperature use. These are high cost, more so when a pin-hole is needed.
Commercial threaded end-plugs. These devices are threaded like the bolts mentioned above, but use an Allen drive to thread them in. They are made of anodized steel. They do not have the big head of the hex-head bolt, so present less of a hazard should they come loose on the roadway. You must specify what size center hole you will be plugging. These are of moderate cost.
This section will describe the various ways to set out hoses for the different types of studies you will be doing. When setting out hoses, there are a few rules of thumb to keep in mind.
Hose tensioning.
After you have anchored and set down your hose, you will need to put it under tension so that it lays straight across the roadway. With normal hose, you need to pull the hose tight, then stretch it about 10% more (for a single lane, you will need to stretch it about 30cm or one foot).
If you are using mini hose, you just pull it up tight, do not attempt to stretch it.
Hose Taping.
When setting down hose, the hose is normally anchored in two spots, the far end of the hose and at the roadway shoulder on the near end. If the traffic is moving at high speeds, you may notice that your hoses are moving noticeably when vehicles travel over it. If this is the case, you will need to consider taping the hose at spots between the anchors. Mini hose tends to move easier since it is under less tension. If the wheel tracks have deep depressions, that can also make the hose move, even at moderate speeds. Note, that when taping down the hose, do not tape in the wheel tracks; avoid taping anywhere wheels would normally run over the hose.
There are two types of tape used for this purpose. Black duct-tape and Mastic tape. Both are fiberglass reinforced, both are very tough.
The Mastic tape has a very thick coating of tar and a very strong adhesive. It can be very difficult to remove at the end of a study, and leave the hose rather sticky. Being mostly tar, this tape can be left on the roadway where it will eventually merge into the roadway. This type of tape really only works well in warmer conditions where it begins merging into the tarmac. It can be applied to wet roadways that are warm, and bond well. In cold climates, it is too stiff and as a result, does not handle well, or bond well to the roadway.
Duct-tape is very thin and has a strong adhesive. This tape is easy to apply. It adheres reasonably well to clean, dry surfaces. Since it does not merge into the tarmac, it does not form nearly as strong a bond as the Mastic tape. In cold climates, it is about your only choice. It will stay down okay for a day or so, depending on traffic loads, but it is not very useful for long studies.
If you need center attachment to keep the hoses from moving and taping is not going to work, you can anchor the middle points using Nylon belt grips.
Placing the hoses.
This section discusses the various configurations of hose placements, based on the type of study you will be doing. We will discuss the placements of hoses for volume only studies, followed by placements of hoses for Speed/Class studies.
Volume only counting:
For volume only counting we will discuss the most common configurations, single hose, two hoses median mounted, and two hoses long-hose/short-hose.
Single Hose.
Often only a single hose is required for volume only counts, depending on the end need of the consumers of the count data. A single hose can be strung across only one lane, or multiple lanes for a single count that is the sum of the traffic in all the lanes (less hose hits that are hidden by other hose hits occurring at nearly the same instant).
Single hoses stretched across multiple lanes will count quite well in low to medium traffic loads, but as the total traffic in vehicles per hour increases, the occurrences of simultaneous hits increases and as a result, the traffic volume being determined by the counter will be lower than reality. For example, with a default dwell time set at 55ms (recommended for volume only counts), at 1000 total vehicles per hour in all lanes, the total volume recorded would be about three percent low. This could actually get worse if the multi-lane counts are being done between signal lights, because the traffic would be coming in groups with the chances of simultaneous hits considerably increased.
Dual Hose Volume Only Setups.
There are a couple of configurations where two hoses are used in volume only counts. The dual hose setup with the counter mounted in the medium is pretty common, especially for split roadways and freeway exits. The dual hose setup for a multi-lane roadway utilizing a short hose and a long hose is a common way of getting volume counts for both directions.
In the long hose - short hose setup shown above, the short hose is stretched across the nearest lane only and the long hose is stretched across the full roadway. The spacing between the hoses is not critical and can be anything convenient. Likewise, since this is a volume only setup, hose lengths are not critical.
Dual Hose Speed/Classify Setups.
Whenever you want speed and/or vehicle classification, you need to use two hoses. There are a few rules that you need to follow so that your speeds and classifications are properly calculated.
The PicoCount 2500 can accommodate a wide variety of hose spacings (L) and calculate good results. Generally, you will have a standard hose spacing that you use for all your different counters. You can specify this default spacing in the preferences dialog of TrafficViewer Pro, so that it does not have to be set for each study.
The accuracy of the speed calculation (and hence the classifications) depends on the parallel hoses being maintained at a precise spacing:
For example, if your default hose spacing is 100 centimeters, a one centimeter error in hose spacing would cause a one percent error in the calculations.
Or if your default hose spacing is 36 inches, a one inch error in hose spacing would cause about a three percent error in the calculations.
The problem of maintaining accuracy gets more difficult with closer spacings:
For example, if your default hose spacing is 10 centimeters, a one centimeter error in hose spacing would cause a 10 percent error in the calculations.
Or if your default hose spacing is 6 inches, a one inch error in hose spacing would cause about a 17 percent error in the calculations.
The diagram above shows a multi-lane setup for speed and classification. Although it is possible to do this, we do not recommend it. For the most accurate results, speed and classification should only be done on a single lane. The multi-lane configuration should only be considered on very low volume roadways where the average total volume is below 100 vehicles per hour.
Now that you have the hoses set up, you need to connect up your PicoCount 2500. As noted previously, the PicoCount 2500 is always counting, there are no switches to worry about, you just need to connect the counter up to the hoses for counting to begin.
Reset the PicoCount 2500. Unless you are deliberately doing a multiple study, you should reset the PicoCount 2500 before each study after you download the prior study data. If this is not done, it will not affect the operation of the PicoCount 2500 in any way, but you will end up with two studies of data in the counter and have to sort it out when generating your reports. To reset the PicoCount 2500, it needs to be connected to a computer with TrafficViewer Pro running (see above). Resetting the counter also sets the counter's date/time to the current date/time of the computer is is plugged in to.
Attach the hoses to the PicoCount 2500. Note that there is a letter "A" embossed into the PicoCount 2500 on the side facing the barbs. The barb nearest is the A hose input. If your hose setup requires a specific hose attachment to the A or the B input you can now attach it accordingly. The PicoCount 2500 hose barbs are designed to take hoses with 4.7mm and 6.3mm (3/16inch and 1/4inch) center holes. In the case of the 6.3mm (1/4inch) holes, the hose needs to be pressed all the way flush to the case to insure a good grip. For the 4.7mm (3/16inch) holes, press the hose on until if firmly resists further pressing. If you are only doing a single hose volume count, make sure to cap the unused input barb so that water and grit does not get into the unused channel.
Verify the hose connections. If you have purchased a CountBuddy, you can easily verify that the PicoCount 2500 is detecting and counting hose hits correctly. Once the hoses are connected, simply plug the CountBuddy into the communications connector on the PicoCount 2500. When you first attach the CountBuddy, both LEDs (Red and Green) will blink together, once, to indicate that it is communicating with the PicoCount 2500. Now whenever a vehicle drives over the hoses, the appropriate LEDs will blink (Green is A hose, Red is B hose). If the LEDs are blinking correctly, then data is being recorded correctly and your hose connections are good. If the LEDs are not blinking as expected, check you hose connections very carefully for correct seating, pinching of the hoses at the grips, or splits and tears in used hose. Alternatively, if you have a laptop handy, you can connect to the PicoCount 2500 with TrafficViewer Pro and click on "Live Data View". A pair of counters will pop up (See Live Data View description above) showing the total of the A hose hits and the B hose hits since you started the Live Data View. These counter show the actual axle hits, so for a car, you should see both the A and the B counts advance by 2 each time a car runs over the hoses.
Normally, at the end of a study, you would disconnect the PicoCount 2500 from the hoses and take the counter back to your sevice vehicle or office to download the data. However, you can download the data at any time, even while the PicoCount 2500 is connected up gathering data, if you have a laptop with TrafficViewer Pro installed.
Once your study is complete and you have disconnected the PicoCount 2500 from the hoses you are ready to download your data. Next connect the PicoCount 2500, with the appropriate download cable, to your PC running TrafficViewer Pro. Then begin communications with the PicoCount 2500 by clicking on the Auto-Detect or the Connect button.
Once the data has been successfully downloaded and configured you are ready to generate your reports of the data. To create a report click on the Print Reports button in the Data Overview panel.
| Power: |
|
| Internal Battery: | 3.0Vdc Lithium type |
| Battery Life: | 10 Years minimum |
| Memory: |
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| Memory Type: | Non-Volatile NAND Flash |
| Memory Size: | 250 MegaBytes |
| Data Retention: | 20 Years minimum |
| Communications: |
|
| Type: | RS-232 ASCII Serial |
| Data Frame: | 8 data bits, 1 stop, no parity |
|
Data Rates: |
115,200 Baud normal 921,600 Baud download |
| Environmental: |
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| Operating Temperature Range: |
-40 F to +158 F -40 C to +70 C |
| Relative Humidity: | 5 to 100% |
| Water Resistance: | Can operate immersed in water |
| RoHS Compliance: | Yes |
| Physical: |
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| Dimensions: |
4.00 x 2.00 x 0.90 inches 102 x 51 x 23 mm |
| Weight: |
7 oz 200 grams |
| Download Connector: | Conxall Mini-Con 4 pin circular |
| Input Air Hose: |
3/16 - 1/4 inch ID 4.75 - 6.35 mm ID |
| Enclosure Materials: | Gold anodized aluminum and stainless steel |