Bp gfor sttc_oct_26_2011


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Installation of road tube (MC5600) and programming of roadside unit (RSU).

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Bp gfor sttc_oct_26_2011

  1. 1. Best Practice Guide for Short Term Traffic Surveys October 2011 Page 1 of 70
  2. 2. 5.5 New SitesTo allocate a new site 1. Step 1. 2. Step 2. 3. Step 3. 4. Etc. Page 25 of 70
  3. 3. 5.6 Special Note for Speed SurveysMost traffic studies will only require a survey at one point on any traffic section. Speed surveys, onthe other hand, may attempt to characterise speed at various points along a given traffic section. Fix X – Speed Surveys Diagram showing speed survey sites allocated to multiple points within a traffic section, with precise definition of SLK at each site (to facilitate any repeat surveys).Careful liaison with stakeholders is crucial to the success of speed surveys, to ensure that the sitesplanned meet their information needs.Accurate site identification is also very critical for enforcement purposes and for follow-up studies.Note: To facilitate later site identification for speed surveys, it may be necessary to included additional information in the Site Description, e.g. nearest house number or other significant feature. Page 26 of 70
  4. 4. 6 Site SelectionSite selection is the process of identifying the physical location for placing traffic survey loggers andsensors. Whilst site placement considerations are an integral part of survey planning, the selection ofactual survey sites should be regarded as a separate process.Site selection is almost always performed in the field by the Survey Supervisor or by otherssufficiently familiar with short term traffic surveys and the goals of the particular traffic study.When selecting physical survey sites, several factors must be considered, including: Safety and ease of installation. Data quality. Information needs of the survey program.Prior to commencing any equipment installation, the Survey Supervisor must review and approve theselected locations.6.1 Volume CountingIn the context of this Guide, volume counting is the process of gathering only indicative vehiclevolumes using a single sensor installed across the lane or carriageway. Traffic volume counting isgenerally only performed in circumstances where site constraints prevent the gathering of classifiedvehicle data and where vehicle classifications and speeds are not required.6.2 Vehicle ClassificationIn the context of this Guide, vehicle classification is the process of gathering vehicle classification andspeed data using paired sensors.Vehicle classification surveys are preferred where possible, as they provide the maximum vehicleinformation.6.3 Characteristics of Suitable Survey Sites6.3.1 Safety Visibility. Approaching drivers must be able to clearly see the installers, and installers must have an unobstructed view of any oncoming traffic. Pedestrian and cyclist safety must not be compromised by any short term traffic survey. Sensors must not be installed across footpaths.Note: Sites must be selected to allow for the safe installation of survey instruments and sensors. This requirement takes precedence over any other requirement.Note: UNDER NO CIRCUMSTANCES are surveys to be carried out where tubes are required to traverse footpaths or bicycle paths. Page 27 of 70
  5. 5. 6.3.2 Escape Routes Installers must be physically able to exit the roadway without obstruction. Sites must be selected so that installers have at least two escape routes.Note: UNDER NO CIRCUMSTANCES are surveys to be carried out where installers would be required to negotiate any obstacle (eg guard rail, barrier fencing) to exit the road way.Note: Narrow median islands are not considered to be a safe refuge.6.3.3 Road Condition The road must be in suitable condition to retain any fasteners (nails, screws) being used to retain the sensors (tubes) for the survey duration. Road surface must allow installers to affix the sensors without excessive effort or delay. Concrete pavements may require pre-drilling. Avoid any areas of severe rutting, potholing, significant change of grade or other road damage. Poor road condition may affect driver behaviour and vehicle performance, spoiling the validity of road usage data at the affected point. Sites on bridge decking will require engineering permission before any installation.6.3.4 Road Geometry Avoid selecting sites where vehicles are altering their trajectory. Avoid selecting sites where vehicles are entering and exiting side roads or drivewaysNote: Vehicles crossing the sensors at a non-perpendicular angle may be recorded with an incorrect speed and wheelbase.6.3.5 Traffic Conditions When selecting a site that is representative of an entire traffic section, ensure that vehicles are free- flowing and travelling at the maximum speed for that particular section. When selecting sites, the possibility of kerbside parking needs to be considered. Avoid locations where parked cars may impact normal road usage. Avoid locations with excessive queuing. Surveys during periods of heavy congestion or queuing will usually result in poor quality data.6.3.6 Anchor Points Select sites with suitable anchor points for securing roadside data loggers. Trees, power poles, guide signs may be suitable anchor points. An eye bolt or a secure picket or post may be installed temporarily to provide a suitable secure anchor point. Fig X. Sign used as anchor Fig X. Temporary eye bolt anchor Page 28 of 70
  6. 6. Note: Smaller signs (e.g. Keep Left) may not provide adequate security.Note: Avoid anchor points in roadside culverts if flooding may occur during the survey period.Note: UNDER NO CIRCUMSTANCES should any of the following be used as anchor points: Private property (e.g. letterboxes, garden ornaments). Pedestrian facilities (e.g. grab rails). Drains, gratings or access covers. Any object within a rail reserve.Note: When selecting anchor points, be aware of: Any possible interference. Potential for vandalism that may result in loggers being placed in hazardous positions. Pedestrian behaviour in the vicinity. Page 29 of 70
  7. 7. 6.4 Lane Numbering at Multi-lane Vehicle Classification SitesNearly all vehicle classification surveys are carried out at sites comprising more than one lane, and aretherefore performed using multiple loggers. Yet the site ID almost always refers to all lanes at thesurvey location. Therefore, a unique lane number must be assigned to each lane to distinguish datagathered from each logger used at the same site.To Establish Unique Lane Numbers 1. Determine the road’s primary direction for the traffic section or location to be surveyed. 2. Facing towards the primary direction (North or East), sequentially number each lane from the left, starting with Lane 1. Fig X. Lane NumberingWhen selecting survey locations for multi-lane sites, consideration needs to be given to the placementof all loggers required to survey the entire site.Note: The lane numbering method as described above is different from the method used elsewhere in Main Roads, to ensure that each logger has unique Header information.6.5 Single Carriageway Bidirectional Vehicle Classification SitesThere is no rule-of-thumb for when a single logger can be used for vehicle classification surveys ofbidirectional traffic. If the occurrences of two vehicles simultaneously crossing the tubes is very low,then data quality will be very good. As the number of simultaneous crossing events increase, dataquality will decrease. It is a matter of assessing the convenience of a single unit, against theacceptable data quality for any given site. Page 30 of 70
  8. 8. 6.6 Multi-lane Uni-directional Vehicle Classification SitesNote: UNDER NO CIRCUMSTANCES should a single logger be used to gather vehicle classification data at multi-lane uni-directional sites. Data gathered in this manner will frequently contain many errors due to simultaneous vehicles travelling in the same direction. WARNING – DO NOT install paired tubes for vehicle classification surveys across two or more lanes with the same flow direction. This will result in erroneous classification data.6.7 Site MarkingSite marking is recommended for: Large and complex surveys. Precise logger placement for location-critical studies (i.e. speed surveys). Surveys in metropolitan and built-up areas. Sites scheduled for repeat or follow-up surveys. Surveys where logger installation must occur at night.Site marking should only be carried out at sites after approval by the Survey Supervisor.Adequate site marking will unambiguously identify the survey location.Equipment installers must be familiar with any site marking and be readily able to locate any markedsites.Note: It is recommended that sites be marked with a green raised pavement marker placed in the carriageway, with the Site ID stencilled with yellow paint adjacent to the edge line. Fig X. Site marked with yellow stencilled paint Fig X. Site marked with green markerNote: Raised pavement markers may only be placed in accordance with Main Roads guidelines. Page 31 of 70
  9. 9. 7 Equipment Installation7.1 Safety Notice – Traffic Volume LimitsNote: UNDER NO CIRCUMSTANCES should short term traffic survey equipment be installed on any carriageway during periods when individual lane volumes exceed 100 vehicles per hour. Installing tubes on high volume and high speed roads may pose significant risks to installers and other road users.Note: All traffic surveys must be carried out with appropriate traffic management.Note: If available, previous traffic counts in the vicinity may provide a guide as to whether lane volumes exceed 100 vehicles per hour during the proposed installation period.7.1.1 Night-time InstallationAs traffic data is frequently required from roads with high traffic volumes, it is often necessary toschedule short term traffic survey equipment installations at night when vehicle flows have subsided.7.2 Traffic ManagementTraffic management must be in accordance with all standards.7.2.1 SpotterWhen installing short term traffic counting equipment, it is recommended that one installer act as aspotter to warn of dangerous situations. The spotter must be continuously monitoring approachingtraffic whilst other installers are on or near the road.7.3 VehicleThe installers’ vehicle is an integral safety component. It must be equipped with rotating or flashingyellow beacons that remain visible to approaching traffic at all times during equipment installation,including logger setup at the roadside.7.4 Safety EquipmentInstallers must wear appropriate personal protective equipment, including protective footwear andhigh visibility jackets, when working on or near the road.Note: UNDER NO CIRCUMSTANCES should installers exit the vehicle prior to equipment installation if not already wearing an approved high visibility jacket.Protective gloves and eyewear must also be worn when required. Page 32 of 70
  10. 10. 7.5 Traffic Survey Equipment Traffic data logger Logger must have sufficient battery life and memory for the expected or required survey duration. Compatible notebook or netbook computer Installed with latest logger operating software. A 12 volt car charging adaptor is recommended. Ruggedising kits may be available for added durability. Communications cable Compatible with traffic data logger. Connects computer to logger for setup, data unload and other logger operations. Rubber pneumatic road tube sensor Secured to the road to detect passing axles. Available in 30m rolls or 100m spools. Road nails 50mm hardened nails specifically for traffic surveys, not suitable for gravel roads. Galvanised deck spikes may provide sufficient anchorage for gravel roads. Cleats Suitable for fastening Rubber pneumatic road tube sensor, maintaining the required tube tension for the survey duration. “Figure-8” cleats (illustrated) are preferred, being light yet sufficiently durable for most traffic surveys. Centre-lane flaps To provide additional sensor stability and durability. May be used as a saddle over the tube, using two nails, or folded over the tube and secured with one nail. Page 33 of 70
  11. 11. Textile-backed bitumen tape (“Bitulastic” tape) An alternative to centre-lane flaps, cut to the desired length. Used as saddles over the tube. Only suitable for dry road conditions.Note: Bitumen tape does not replace the use of cleats, as it does not maintain tube tension. Bitumen tape must be thoroughly amalgamated with the road surface.7.5.1 Other Items Spare battery packs Available from logger manufacturer. Only use recommended battery packs. Hex ball driver For opening logger to replace battery. Padlock, chain or security strop For anchoring and securing logger at survey location.7.6 Installation Tools Tape measure or calibrated spacing gauge. Chalk or lumber crayon. Sharp knife or side cutters. Heavy Duty Claw Hammer, heavy ball hammer or heavy mallet. Crowbar. A cordless drill with interchangeable screwdriver bits may be required for concrete roads. Page 34 of 70
  12. 12. 7.7 Sensor Configurations – Vehicle ClassificationFor short term traffic surveys where actual vehicles are required with class and speed information,paired tubes are installed with a precise spacing. Almost always, paired tubes are installed in eachlane, with full site coverage requiring a logger for every lane. Single lane Paired tubes installed across a single lane. Two lane bidirectional Paired tubes installed across a two-lane bidirectional carriageway. Note: A single logger can be used for bidirectional traffic only if the occurrences of two simultaneous vehicles crossing the tubes is very low. Two lane – separate tubes Paired tubes installed in each lane. Can be used for any flow direction. Used at sites where anchor points are widely separated on opposite sides of the carriageway. Two lane – shared tubes Shared paired tubes installed across two lanes. Knots at the centreline isolate each lane. Simplifies installation at multi-lane sites. Can be used for any flow direction. Can only be used at sites where anchor points are closely spaced on opposite sides of the carriageway. Page 35 of 70
  13. 13. 7.7.1 Blocker or No-Count TubesSpecialised non-compressible tubes, often referred to as “blocker” or “No-count” tubes, are availableto isolate lanes, by masking the axle hits in the near lanes. Blocker tubes allow surveys at multi-lanesites where anchor points are unavailable for the lane being surveyed. Examples: Four lane road with no central median, or Carriageways with three or more lanes. Two lane – “blocker” or “No-count” tubes Paired tubes installed in each lane. Can be used for any flow direction. Used at sites where anchor points are only available on one side of the carriageway. Blocker tube can be extended into other lanes (eg three loggers covering three lanes).Note: Blocker tubes may be difficult to install and may not remain non-compressible for the survey duration. Special tools may also be required for installation – check with the manufacturer. Furthermore, additional traffic control will generally be required, with longer installation times across multiple lanes.7.7.2 Vehicle Classification – Installations to Avoid Two or more uni-directional lanes Error prone. Tends to overestimate heavy vehicles. Crossover Difficult to install. Very error prone. Not supported by software. Page 36 of 70
  14. 14. 7.8 Sensor Configurations – Volume CountingFor short term traffic counting where only indicative volumes are required, a single tube may beinstalled across the lane or carriageway. Further lane or carriageway differentiation can be obtainedusing a second tube. Single tube May be installed across any number of lanes or the entire carriageway. Provides indicative traffic volume only. Dual tube – “Split” configuration Short tube – long tube combination allows directional or lane-based indicative traffic volumes. Volume in the far lane (i.e. the lane covered only by the long tube) is derived using software by subtracting short tube counts from the long tube counts. Dual tube Logger installed in the median. Two tubes, one per lane or carriageway, provides indicative volumes of each direction. Page 37 of 70
  15. 15. 7.9 Installation ProcedureThe following section discusses the installation of a logger using a classification tube layout. The tipsand techniques discussed here can be carried over to traffic count layout installations.7.9.1 Typical Tube Layout – SeparateThe following diagram depicts a generalised tube configuration for use with a single logger. Fig 7. Separate Tube Fig-8 cleats Centre-lane flap Centre-lane flap Textile-backed Fig-8 cleats Knots (used as a saddle) (used folded) bitumen tape Fig 8. Separate Tube Layout Page 38 of 70
  16. 16. 7.9.2 Typical Tube Layout – SharedThe following diagram depicts a generalised tube configuration for use with a two loggers, one ateach end. Fig 9. Shared Tube Fig-8 cleats Knot (or Knot (or Fig-8 cleats other airtight other airtight blockage) blockage) Fig 10. Shared Tube LayoutTo attach a Figure-8 Cleat 1. Place one end of the pneumatic tube over the large loop of a Figure-8 Cleat. 2. Twist the Figure-8 Cleat to form a second loop, and slide over the end of the pneumatic tube. 3. Bunch the two loops together, and pull the tube through as required. Page 39 of 70
  17. 17. To install pneumatic tubes (suggested method) 1. Prepare two tubes of equal length, and sufficiently long to cover the required lanes, and reach the logger securing point. 2. Using a tape measure, or one meter stick, mark the one meter Fig X. Spacing tubes with gauge tube spacing on the road with a lumber crayon or chalk. 3. Attach Figure-8 Cleats to one end of each tube, using one or two per tube. 4. Seal the same end of each tube with two knots, adjacent to the cleats. 5. Secure both tubes to the road, using a road nail through the eyelet of each cleat. 6. Attach Figure-8 cleats to the curb side of each tube, using one or two per tube, and secure to the road using road nails. Ensure that the tubes are parallel to each other, and perpendicular to the direction of vehicle travel. Fig X. Centre flap as saddle 7. Double-check that the tube spacing is one meter. 8. Stretch each tube 10% to 15% to minimise lateral movement. Use a cable tie around the curb side cleats if necessary to prevent slippage. 9. Ensure that the tube length from the wheel path to the logger’s air sensors is exactly the same. A difference in length will result in incorrect speeds and wheelbases. 10. Attach canvas flaps as required using two road nails per flap. This will minimize lateral movement over long distances. Using one in the centre of each lane, in addition to between two lanes will maximize data quality. Short lengths (8 – Fig X. Centre flap used folded 10cm) of textile-backed bitumen tape can be used as an alternative. 11. Remove the logger’s inner tray from the stainless steel case and feed both tubes up through the handle. 12. Place the PVC main system unit next to the tray and attach each tube to the appropriate air sensor. Remember to use the convention of the A tube being the first hit by a vehicle travelling in the lane closest to the logger. Use the logger’s Status LEDs, or the Traffic View on a mobile PC, to verify the correct tube connections. 13. Place the PVC main system unit into the tray, and push each tube into the trays respective locking cut-outs, as shown in Fig X. Bitulastic tape used as saddle the diagram below. Page 40 of 70
  18. 18. 14. Slide the tray into the outer case, and secure the logger using a padlock through one of the holes in the handle. Page 41 of 70
  19. 19. 7.10 A Final ChecklistThere are four major items to be checked when installing road tubes for classification surveys.When installed, tubes must be: Correctly spaced. Parallel to each other. Perpendicular to the direction of vehicle travel. Equal length from wheel path to logger. This must be checked after tensioning the tubes. Page 42 of 70
  20. 20. 8 Logger SetupTo operate MC5600 logger, a notebook or netbook computer running MTE will be required.MCSetup is the component of MTE used to interface with the MC5600 and is used for all loggeroperations.The MC5600 records every axle strike, regardless of the survey requirements. Operating the MC5600is therefore very simple, only requiring setting of the logger’s header details.The following display is the start up screen for the MCSetup application.With MCSetup, the large buttons are used to perform the following tasks: Check the status of the logger; Setup the logger to start a new survey; Unload data from the logger, including dynamic graph of axle hits; View vehicles and axle hits in real-time to verify sensor installation; Change data channels – not used with the MC5600.Other logger diagnostics are available in the menu. Page 43 of 70
  21. 21. 8.1 MCSetup’s Preferences MCSetup’s Preferences Dialog BoxPreferences will need to be set when starting MCSetup for the first time.To change Preferences at any time, Choose View menu » Preferences.Use MCSetup ‘Preferences’ to select communications port. In the event that MCSetup will notcommunicate with the logger, check the comms port in ‘Preferences’.Choose the folder where unloaded data will be stored, then use the buttons for further sub-grouping.MCSetup will create folders for you if they don’t already exist. Base folder Further sub-folders, created automatically during unloadMCSetup uses a combination of site ID, plus day and month of unload to create unique dataset names.Choose ‘long file names’ to create long Windows-only file names. Page 44 of 70
  22. 22. 8.3 Checking the LoggerThe status dialog box in MCSetup displays a snapshot of the logger’s current status.The dialog box pictured below opens when clicking on the RSU Status button, displaying statusinformation. The status information is divided into five pages: Data, RSU, Battery, Sensors andMemory. It is recommended to conduct a logger status check during a survey to review the datacollected and detect if any potential problems may arise.8.3.1 Data PageThe Data page displays the information entered into the logger during setup. Details here are coveredlater in the Setup section.8.3.2 RSU PageThe RSU page contains information about the logger’s status. The ‘Ident’ field displays the logger’sunique serial number. ‘Status’ text is important and should be noted when checking a logger’s status. Watch the Status text change after performing Setups and Unloads, etc. Page 45 of 70
  23. 23. 8.3.3 Battery PageThe Battery page displays the logger’s voltage of the non-rechargeable alkaline battery pack. Batterylife remaining is based on current consumption, and the battery pack’s discharge characteristics,which is active for 290 days. Typically a MC5600 logger will stop logging once the alkaline battery isreduced to 4.8 volts.Note that the RAM backup battery receives its power from the main battery, and should alwaysremain in the “green” zone.8.3.4 Hits PageThe Sensors page shows information about the axle hit data currently in the logger’s memory. Forclassifier surveys an A/B ratio of between 95 – 105% is acceptable. If there is a problem with thesensor balance, MCSetup will issue a warning when clicking the RSU status button.8.3.5 Watch for sensor imbalance, which may indicate tube faults Page 46 of 70
  24. 24. Memory PageThe Memory tab displays a graphical representation of the logger’s memory. When the logger’smemory is full, it will stop recording axles. The Memory page contains a run-time estimate to beused as a guide.8.4 Page 47 of 70
  25. 25. 8.5 Logger SetupNote: Before commencing a new survey, check that the computer’s date and time is correctly set.MCSetup’s Setup dialog box allows you to quickly setup for a new survey: MCSetup Header Field Values to be entered or selected Site The site ID from the Reporting Centre. Up to 5-digits, zero-filled (e.g. 00123). Optional. May be set to the current latitude and longitude if obtained from an optional Attribute GPS unit. Operator Operator’s initials. Start time Set to start immediately, on the next hour, midnight tonight or defer to midnight Sunday. The site description from the Reporting Centre. May include the site’s posted speed Site description limit in angle brackets, eg <60>. If used, append the posted speed limit to the end of the Reporting Centre’s description. Sensor layout Choose either “Paired” for classification surveys, or the other options for traffic counts. Lockout Choose Lockout from the menu (usually either 10ms or 30ms). Direction Choose the flow direction over the tube (see note below). Set to “0” for two lane bi-directional classification sites, otherwise number each lane Lane separately as described in the section on “Lane Numbering”. Spacing Click “Set spacing” to enter physical tube spacing, checked and verified beforehand. Page 48 of 70
  26. 26. Note: For classifier layouts, choose a Direction that characterises the flow directions over the tubes. For volume layouts, choose the flow over each tube separately.Note: The logger’s tube inputs (i.e. the brass spigots) are clearly labelled ‘A’ and ‘B’. The tubes only assume their ‘A’ or ‘B’ identity after connecting the tubes to the logger. Fix X – Notebook computer being used to setup MC5600 logger8.6 Example Site DescriptionsThe following tables give examples of acceptable site descriptions, and some common descriptionsthat are not compatible with Reporting Centre. Table 3. Descriptions compatible with Reporting Centre Example Description Notes Great Eastern Hwy E of Belgravia St Acceptable site description 60 km/hr posted speed limit appended in Great Eastern Hwy E of Belgravia St <60> angle brackets Although not strictly required, SLK can be used for precise site location, e.g. for speed Great Eastern Hwy E of Belgravia St, 4.36 SLK studies. (Note: SLK is linked to the unique Site ID in Reporting Centre). Table 4. Descriptions NOT compatible with Reporting Centre Example Description Notes Full road designations are not required. Great Eastern Highway E of Belgravia Street Instead, use standard abbreviations. All capitals is not required. Instead, use GREAT EASTERN HWY E OF BELGRAVIA ST upper and lowercase letters. Main Roads’ road designations and other H003 GEH E of Belgravia St road abbreviations are not required. Instead, use gazetted road names. Full compass direction from nearest Great Eastern Hwy east of Belgravia St intersection is not required. Instead, abbreviate as “N”, “E”, “S” or “W”. Page 49 of 70
  27. 27. 9 Mid-Survey CheckingMid-survey checking is recommended for: Surveys of seven or more days duration; or Surveys providing critical data for stakeholders.Checking can simply be a quick drive-by to ensure that the tubes are intact. More detailed inspectionmay be required for critical surveys.Note: If a mid-survey data snapshot is required, the logger may be unloaded, but with logging continuing.9.1 Monitoring a SurveyDuring a survey it is advisable to regularly check your site to ensure that any loss in data quality isdetected before a survey is completed.Note: Remember MC5600 loggers store every axle hit. Traffic views in MCSetup are therefore transient representations of the actual data and MUST BE USED WITH CAUTION. Page 50 of 70
  28. 28. 10 Data Unload DON’T CHANGE THE DEFAULT FILE EXTENSION Uncheck “Stop the RSU after unloading data” to unload the data so far, but continue data gathering (i.e. for a mid-survey checking). Check “Stop the RSU after unloading data” to complete the survey.Note: DO NOT change the file extension (eg ‘EC0’, ‘EC1’, etc). Changing the default file extension will make it impossible of other MetroCount programs to locate and identify files.Note: After unloading data, including the option to “Stop the RSU after unloading data”, the data is retained in the logger until the next setup. Page 51 of 70
  29. 29. 10.1 Data Quality Check During UnloadThe easiest method of performing a data quality assessment mid-survey is to perform an Unloadwithout stopping the RSU. This will leave the logger active, while still displaying the A and B tube hitplots as the data transfers. Watch the sensor balance plot as your data unloads. Immediately spot sensor imbalance, indicating a possible tube fault. Page 52 of 70
  30. 30. 11 Equipment RemovalEquipment removal is simply the reversal of the physical installation process.As with equipment installation, the same requirements apply with respect to safety, traffic control,traffic volume limits, etc. Page 53 of 70