You are here: Home > Support > Hardware Support > Road Tube Installation
Proper road tube installation is very important for collecting accurate data with your TRAX. The road tube and the
TRAX's air switches comprise the sensing device for the unit. As with all receivers, the sensor has to be
functioning properly to record reliable information. With this in mind, examine your installations carefully and be
absolutely certain that your unit is recording data as programmed.
Road tubes should be replaced on a fairly consistent basis. Older tube will eventually develop splits that can
allow water to enter. When an air pulse is received, this water can be forced back into the unit’s air switch,
potentially causing serious damage. Do not risk expensive repair bills by trying to squeezing a few extra studies
out of old tube. One rule of thumb is to replace tubes after 30 days of use.
TRAX's air switches comprise the sensing device for the unit. As with all receivers, the sensor has to be
functioning properly to record reliable information. With this in mind, examine your installations carefully and be
absolutely certain that your unit is recording data as programmed.
Road tubes should be replaced on a fairly consistent basis. Older tube will eventually develop splits that can
allow water to enter. When an air pulse is received, this water can be forced back into the unit’s air switch,
potentially causing serious damage. Do not risk expensive repair bills by trying to squeezing a few extra studies
out of old tube. One rule of thumb is to replace tubes after 30 days of use.
Types of tube
There are currently two main types of tube that are used for data collection: standard
'O' tube and mini-tube.
Standard O tube is a circular shape tube with an inside diameter of either .25 or .187
inches and an outside diameter of .60 inches. This tube has been used in the
industry for decades with a wide range of recorders.
Mini-tube is a much smaller and lighter version of standard O tube that has become
very popular in recent years. This tube has an inside diameter of .187 inches and an
outside diameter of .365 inches.
There are currently two main types of tube that are used for data collection: standard
'O' tube and mini-tube.
Standard O tube is a circular shape tube with an inside diameter of either .25 or .187
inches and an outside diameter of .60 inches. This tube has been used in the
industry for decades with a wide range of recorders.
Mini-tube is a much smaller and lighter version of standard O tube that has become
very popular in recent years. This tube has an inside diameter of .187 inches and an
outside diameter of .365 inches.
| ||||||||||||||||||
We recommend use of mini-tube for most applications. It is easier to install and use than standard O tube and
testing has shown it to be effective for up to one million axle hits under normal conditions.
A third type of tube, D tube, is also used for some high speed/high volume applications.
testing has shown it to be effective for up to one million axle hits under normal conditions.
A third type of tube, D tube, is also used for some high speed/high volume applications.
Recommended Tube Length
Tube length is very critical in order to record accurate vehicle data. The following guidelines should be followed
for all studies regardless of simplicity. The lengths listed for each study below have shown to provide the best
results based on extensive testing.
Tube length is very critical in order to record accurate vehicle data. The following guidelines should be followed
for all studies regardless of simplicity. The lengths listed for each study below have shown to provide the best
results based on extensive testing.
L2, L8, L11, L12 (Short tube, long tube setups)
To ensure the pulses from the road tubes arrive at the counter in the proper
order, the tube length must be the same from the edge of the road to the
counter. This will allow the pulse from the short tube to arrive before the pulse
from the long tube. If the A tube (short tube) of a layout has a distance of 26
feet from the edge of the road to the counter, then the B tube (long tube) must
have this same distance. In other words, the short tube must be one exactly one
lane width shorter than the long tube length.
To ensure the pulses from the road tubes arrive at the counter in the proper
order, the tube length must be the same from the edge of the road to the
counter. This will allow the pulse from the short tube to arrive before the pulse
from the long tube. If the A tube (short tube) of a layout has a distance of 26
feet from the edge of the road to the counter, then the B tube (long tube) must
have this same distance. In other words, the short tube must be one exactly one
lane width shorter than the long tube length.
Hardware Support
Proper Road Tube Use and Installation
Proper Road Tube Use and Installation
The following installation instructions cover standard O tube and mini-tube. These directions will assist you in
placing your road tubes correctly on the road surface with confidence and a minimum of effort.
placing your road tubes correctly on the road surface with confidence and a minimum of effort.
| A slideshow demonstration of the proper techniques for installing road tubes is available for viewing. We recommend viewing this demonstration if you are new to the process of installing road tubes, or would like additional tips on installation. |
L1, L3, L4, L5, L6, L7, L9, L10 (Long tube setups)
To encompass all types of vehicles and speeds, a tube length of 50 to 60 feet
is recommended for standard O tube while a length of 40 to 60 feet is
recommend for mini-tube. These length should satisfy all requirements for
normal street, road, highway and interstate traffic patterns. All tubes used for
these types of layouts must be the same length.
To encompass all types of vehicles and speeds, a tube length of 50 to 60 feet
is recommended for standard O tube while a length of 40 to 60 feet is
recommend for mini-tube. These length should satisfy all requirements for
normal street, road, highway and interstate traffic patterns. All tubes used for
these types of layouts must be the same length.
Example: You are using mini tube to install an L11 layout across two lanes of traffic and each lane is twelve feet
wide. In order to ensure that the distance the air pulse has to travel from the edge of the road to the counter is
the same for all tubes, you should use 38 feet for the short tubes (A & C) and 50 feet for the long tubes (B & D).
The short tubes will be installed over only one lane (12 feet), leaving 26 feet of tube back to the TRAX. The long
tubes will be installed over two lanes (24 feet), but since they are 50 feet long, you will still have 26 feet back to
the TRAX. It is very important that the air pulses travel over the same distance when two or more tubes are used
to record data.
To accommodate the required length of tube, brass splices may be used, if necessary. The splices are
approximately three (3) inches long, hollow and do not restrict the flow of air. Do not use the splices on the
roadway itself, only on the section of tube after the clamp nearest the TRAX.
wide. In order to ensure that the distance the air pulse has to travel from the edge of the road to the counter is
the same for all tubes, you should use 38 feet for the short tubes (A & C) and 50 feet for the long tubes (B & D).
The short tubes will be installed over only one lane (12 feet), leaving 26 feet of tube back to the TRAX. The long
tubes will be installed over two lanes (24 feet), but since they are 50 feet long, you will still have 26 feet back to
the TRAX. It is very important that the air pulses travel over the same distance when two or more tubes are used
to record data.
To accommodate the required length of tube, brass splices may be used, if necessary. The splices are
approximately three (3) inches long, hollow and do not restrict the flow of air. Do not use the splices on the
roadway itself, only on the section of tube after the clamp nearest the TRAX.
Tube Placement
Tubes should be placed exactly perpendicular to the flow of traffic to prevent double counting. When using two
or more tubes that must be set at specific distances from each other, always use a tape measure or ruler to
measure from the center of each tube to determine the proper spacing. In short tube, long tube setups, the short
tube should be installed to the zone line (center of the highway). Observe traffic to be sure that vehicles in the
outer lane are not coming in contact with the short tube.
Tubes should be placed exactly perpendicular to the flow of traffic to prevent double counting. When using two
or more tubes that must be set at specific distances from each other, always use a tape measure or ruler to
measure from the center of each tube to determine the proper spacing. In short tube, long tube setups, the short
tube should be installed to the zone line (center of the highway). Observe traffic to be sure that vehicles in the
outer lane are not coming in contact with the short tube.
Installation - Round Tube (.187 or .25 ID x .60 OD)
Round tube should be stretched one foot for every ten feet of roadway when being installed. Each tube should
be secured at each end of the roadway by using a galvanized C-Clamp, Chinese Finger, Figure 8 Grip or an
End Plate. Whichever is used, ensure the proper nail size is used. Use the longer nail size (normally 2 1/2 inch
or longer) in hot weather due to the softness of the asphalt. In cold weather applications, the asphalt becomes
harder, making it more difficult to drive in the nails. In this situation, smaller nails (1 1/2 inch) can be used.
Next, secure the tube on the traveled portion of the road surface by using mastic. As a minimum, one piece of
mastic should be placed on the zone line (middle of the road) and two pieces of mastic should be placed in each
lane. Additional mastic should be used as deemed necessary to prevent the tube from moving when stuck by a
vehicle.
Round tube should be stretched one foot for every ten feet of roadway when being installed. Each tube should
be secured at each end of the roadway by using a galvanized C-Clamp, Chinese Finger, Figure 8 Grip or an
End Plate. Whichever is used, ensure the proper nail size is used. Use the longer nail size (normally 2 1/2 inch
or longer) in hot weather due to the softness of the asphalt. In cold weather applications, the asphalt becomes
harder, making it more difficult to drive in the nails. In this situation, smaller nails (1 1/2 inch) can be used.
Next, secure the tube on the traveled portion of the road surface by using mastic. As a minimum, one piece of
mastic should be placed on the zone line (middle of the road) and two pieces of mastic should be placed in each
lane. Additional mastic should be used as deemed necessary to prevent the tube from moving when stuck by a
vehicle.
Installation - Mini-Road Tube (.187 ID x .375 OD)
Since mini tube is smaller and lighter than standard round tube, less hardware is required to install the tubes.
Also, mini tube should not be stretched when installed, just placed on the road.
Webbing can be used to secure the tube at each end of the roadway. You may tie a knot at the far end of the
tube instead of using an end plug or PK nail. Since the mini tube is light and low profile, you may use duct tape or
two-inch mastic to secure the tube to the roadway. Generally, three pieces of tape/mastic are sufficient. To
reduce wear and/or breakage of the tape, do not install the tape in the path of the vehicle tires.
When installing a short tube, long tube configuration (L2, L8, L11, L12) you may install both tubes completely
across the road and tie a knot midway of the half tube. This eliminates nailing the half tube on the center line
which can create a safety problem for installation personnel.
Since mini tube is smaller and lighter than standard round tube, less hardware is required to install the tubes.
Also, mini tube should not be stretched when installed, just placed on the road.
Webbing can be used to secure the tube at each end of the roadway. You may tie a knot at the far end of the
tube instead of using an end plug or PK nail. Since the mini tube is light and low profile, you may use duct tape or
two-inch mastic to secure the tube to the roadway. Generally, three pieces of tape/mastic are sufficient. To
reduce wear and/or breakage of the tape, do not install the tape in the path of the vehicle tires.
When installing a short tube, long tube configuration (L2, L8, L11, L12) you may install both tubes completely
across the road and tie a knot midway of the half tube. This eliminates nailing the half tube on the center line
which can create a safety problem for installation personnel.
Checking for Accuracy
Once your tubes are installed and you are collecting data, observe the traffic as it is being recorded to be sure
everything is working correctly. If possible, check the tubes periodically during the study to ensure they have not
been damaged and also to make sure that your data is being recorded as programmed.
Upon completion of your data collection, remove the tubes, clamps, nails and anything else that may be of
danger to the motorists. The mastic may be hard to remove in some instances, especially in hotter weather. In
those cases, it may be left on the highway and eventually it will blend into the asphalt from the flow of traffic.
Once your tubes are installed and you are collecting data, observe the traffic as it is being recorded to be sure
everything is working correctly. If possible, check the tubes periodically during the study to ensure they have not
been damaged and also to make sure that your data is being recorded as programmed.
Upon completion of your data collection, remove the tubes, clamps, nails and anything else that may be of
danger to the motorists. The mastic may be hard to remove in some instances, especially in hotter weather. In
those cases, it may be left on the highway and eventually it will blend into the asphalt from the flow of traffic.