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Traffic Feedback Report SummariesFor additional information e-mail: ltppinfo@fhwa.dot.gov. Report Number: BRE-31 Subject/IMS Table: Absence of CONSTRUCTION_NO
in traffic tables and uncertain meaning of MODIFICATION_NO in
table TRF_MONITOR. LTPP Analysis/Operations Situation: The CONSTRUCTION_NO field is not included in the traffic monitoring tables. This would be very helpful. The table does have a MODIFICATION_NO field but the data dictionary is unclear on what this is. Resolution of Problem/Situation: Problem has been resolved. Report Number: BRE-39 Subject/IMS Table: Add CONSTRUCTION_NO to
table TRF_MONITOR_BASIC_INFO. LTPP Analysis/Operations Situation: Is it possible to add the construction number to the TRF_MONITOR_BASIC_INFO table? This would assist in assigning data to the correct time frame for a section. Resolution of Problem/Situation: A decision on the solution to this problem will be made when the new traffic software is written. Hopefully, when the IMS for traffic is redone, equivalent single-axle loads (ESALs) will be in a separate table and the CN_ASSIGN date can be taken into the calculations and incorporated into the record. Report Number: BRE-43 Subject/IMS Table: Multiple rows in automated
vehicle count (AVC) data for the same
hour. LTPP Analysis/Operations Situation: The level 4 AVC data for section 124000 has multiple rows of data for the same direction, lane, and hour. This occurred in the October 1991 data. The Regional Offices should check the validity of this data. Resolution of Problem/Situation: The Southern Regional Office reviewed the data feedback report and found that it has bad data for October 1991 for section 124000. September and November appear to be correct. The bad data (duplicates) can be manually removed if the Central Traffic Database (CTDB) has the raw data files (which is the only way it can be determined which row to delete). This data was processed before there were any directives to archive the data. Upon examining a few random months in other years, this problem also appears and may be prevalent. A data request from the CTDB will have to be made to obtain the raw data files and the quality control (QC) processing software may need to be run to find any other duplicates that may exist. Report Number: BRE-44 Subject/IMS Table: Zero values in the load
spectra for Site 124000 in Florida. LTPP Analysis/Operations Situation: Site 124000 in Florida has several days of data for which the load spectra for all of the vehicle classes was zero. A problem with the weigh-in-motion (WIM) equipment is suspected for this period. The Regional Office should check the validity of this data. Resolution of Problem/Situation: Level 4 WIM data was reviewed for 124000 and found that weight totals are present within the data. It is unknown why the load spectra show 0. There is no indication that the data is incorrect. By reviewing the raw data, if obtained from Central Traffic Database (CTDB), a definite response can be given on the status of the data. Report Number: BRE-45 Subject/IMS Table: Zero values in the load
spectra for some of the vehicle
classes. LTPP Analysis/Operations Situation: Site 124000 in Florida has several days of data for which the load spectra for vehicle class 5 is zero, but the other vehicle classes have non-zero values. Automated vehicle count (AVC) data indicates non-zero values for class 5 vehicles. The Regional Office should check the validity of this data. Resolution of Problem/Situation: Level 4 data was reviewed for Site 124000 (BRE-45) for all dates listed and found counts for vehicle class 5 for all instances. It is unknown why the load spectra show 0. It is possible that instances with counts were purged during QC. By reviewing the raw data (if obtained from the CTDB) a definite response on the status of the data could be given. Report Number: BRE-46 Subject/IMS Table: Data dictionary for level 3
traffic data. LTPP Analysis/Operations Situation: There is a potential problem with the data dictionary for level 3 traffic data. The data dictionary states that, for line 158-161 of the level 3, the W-4 tables provide yearly volume estimates, but it is actually provides daily volume estimates. It is recommended that the schema be changed to reflect that the estimate is actually a daily volume and not a yearly volume. Resolution of Problem/Situation: The table in question is in fact daily and not annual numbers as suggested. It is however, a summary — not an estimate. The relevant documentation has been changed and will be published with the release of the new analysis software. Report Number: BRE-57 Subject/IMS Table: Data in level 4 traffic
files beyond column 51. LTPP Analysis/Operations Situation: There are test sections which have traffic files with data beyond column 51. These files do not have a sheet 7 to indicate that there were additional traffic classes. Resolution of Problem/Situation: The data beyond column 51 are valid. Columns 52-80 are reserved for optional State data and do not hinder the traffic software processing. No action is necessary. Report Number: BRE-74 Subject/IMS Table: Negative ESALs in table
TRF_MONITOR_BASIC_INFO. LTPP Analysis/Operations Situation: Test section 040161 has negative ESAL estimates in the TRF_MONITOR_BASIC_INFO table. The Regional Office needs to review data for potential errors. Resolution of Problem/Situation: The data has been reprocessed with the corrected ESAL values and re-uploaded to the Regional Information Management System (RIMS). Negative ESAL values were corrected. ESAL calculation software will be available for the June 2000 upload which should prevent this problem from happening. Report Number: EBA-13 Subject/IMS Table: Lack of linked section traffic data for the North Central Region in table TRF_MONITOR_BASIC_INFO. LTPP Analysis/Operations Situation: As evidence by both the TRF_MONITOR_BASIC_INFO data file and a count of records by table and section after the November 30, 1998 upload there is no data on the linked sections of SPS projects in the North Central Region. This includes both the SPS-3 and -4 projects for which only one entry appears and the newly constructed and rehabilitation projects. Instructions on processing traffic data for SPS projects are included in IMS directives 46 and 47 and the instructions accompanying the SPS.dat software from Chaparral which was released in May of 1997. It is recommended that traffic data processing for SPS projects be completed (core sections only) in the North Central Region. Resolution of Problem/Situation:This feedback report has been resolved to the extent possible. Some sections do not have equipment installed or have faulty equipment that has never worked. Traffic data collection is an ongoing problem. Report Number: ERES-BW-61 Subject/IMS Table: LTPP sections missing both
historical and monitoring 80-kn ESAL traffic data and sections
with questionable traffic data. LTPP Analysis/Operations Situation: A number of sections used in faulting data analysis are missing historical and monitoring ESAL data. The list of sections in question was attached to the feedback report. Several sections have questionable trends in ESAL values and truck factor values outside the acceptable range (0.5 to 2.5). Resolution of Problem/Situation: Much of this problem has been resolved as a part of data resolution. Report Number: ERES-BW-72 Subject/IMS Table: Suspicious traffic data in
field ANNUAL_ESAL_W4 in table
TRF_MONITOR_BASIC_INFO. LTPP Analysis/Operations Situation: The annual ESAL values (field ANNUAL_ESAL_W4 in table TRF_MONITOR_BASIC_INFO) for the following sections are suspiciously low. Annual ESALS for Sections 190213-190224 in 1997 were approximately 56,400. This is much lower than the required traffic level (>200,000) at SPS-2 sites. Section 530201 in 1997 had an annual ESAL of 819. This value is way too small. Additionally, the annual ESAL at the same section 530201 is 455,328 for 1998. Resolution of Problem/Situation: Data for 1902** is correct as entered in the IMS. Data for sections 530201 in 1997 has been corrected. This error was due to a site coding problem. Report Number: ERES-BW-81 Subject/IMS Table: Negative
ESALs. LTPP Analysis/Operations Situation: Some of the sections for the Arizona and California SPS-6 sites have negative ESAL values, except for the bare portland cement concrete (PCC) sections 040601, 040602, 040605, 060602, and 060605. Resolution of Problem/Situation: The negative ESAL values were addressed in Feedback Report BRE-75 and corrections were uploaded in March 1, 2000. At the direction of the Technical Services Support Contractor (TSSC), the project level negative ESAL values were removed from the IMS. Report Number: ERES-BW-82 Subject/IMS Table: "Zero" data in table
TRF_MONITOR_AXLE_DISTRIB. LTPP Analysis/Operations Situation: "Zero" data were entered in table TRF_MONITOR_AXLE_DISTRIB instead of "Null" data. Appearance of "Zero" data in the database could result in calculation of erroneous averages when the analyst would want to obtain general traffic characterization of axle weight distribution for a given LTPP site. This feedback was prepared based on review of traffic data for Texas LTPP sites; however, this situation appears to be characteristic for more than one state. Resolution of Problem/Situation: No action is necessary as "zero" data is valid data. Report Number: ERES-BW-99 Subject/IMS Table: Multiple monitoring traffic
data entries for the same year. LTPP Analysis/Operations Situation: While reviewing the traffic monitoring tables using IMS Q3, 2000 level E release, the Data Analysis Technical Support (DATS) team found several instances where multiple data entries exist for the same site and year. The reason is that several modification numbers (key field) were kept in IMS monitoring traffic data tables. A list of sites and years with multiple entries is attached to the feedback report for each of the following three tables: TRF_MONITOR_BASIC_INFO, TRF_MONITOR_AXLE_DISTRIB, and TRF_MONITOR_VEHICLE_DISTRIB. Resolution of Problem/Situation: This problem was due to a data extraction error and not an IMS problem. No action is necessary. Report Number: ERES-BW-100 Subject/IMS Table: Missing data in the
TRF_MONITOR_BASIC_INFO table. LTPP Analysis/Operations Situation: While reviewing the traffic monitoring tables using IMS Q3, 2000 level E release, the Data Analysis Technical Services team found many sites and years for which data are missing from the TRF_MONITOR_BASIC_INFO table but present in the TRF_MONITOR_AXLE_DISTRIB and TRF_MONITOR_VEHICLE_DISTRIB IMS tables. Resolution of Problem/Situation: Resolved. Report Number: ERES-BW-101 Subject/IMS Table: All-zero traffic data
entries in the TRF_MONITOR_* tables. LTPP Analysis/Operations Situation: While reviewing the traffic monitoring tables using IMS Q3, 2000 level E release, the Data Analysis Technical Services team found several instances when all-zero traffic count entries were entered in IMS traffic monitoring data tables. Unless the site was closed to traffic for the entire year, these entries should not be kept as zeros in the IMS database. A list of sites and years with all-zero traffic data entries is attached for each of the following three tables: TRF_MONITOR_BASIC_INFO, TRF_MONITOR_AXLE_DISTRIB, and TRF_MONITOR_VEHICLE_DISTRIB. Resolution of Problem/Situation: Resolved. Report Number: ERES-BW-102 Subject/IMS Table: Records are missing from
table TRF_EST_ANL_TOT_LTPP_LN. LTPP Analysis/Operations Situation: While reviewing the historical record traffic table TRF_EST_ANL_TOT_LTPP_LN using IMS Q3, 2000 level E release, the DATS team found that several sites are not included in the TRF_EST_ANL_TOT_LTPP_LN table but have data in traffic monitoring tables for 1990 or later years. These sites were opened to traffic prior to 1990 and should have a historical traffic record in the TRF_EST_ANL_TOT_LTPP_LN table. A list of sites is attached to the feedback report. Resolution of Problem/Situation: This data could not be entered until Sheet 10 data entry (and Sheet 2) was made available to the regions in the IMS. The DOS/DesqView environment software formerly used is no longer generally available to the regions for use. This data has now been entered and the report is considered resolved. Report Number: ERES-BW-103 Subject/IMS Table: Records are missing from
table TRF_BASIC_INFO. LTPP Analysis/Operations Situation: While reviewing the IMS table TRF_BASIC_INFO using IMS Q3, 2000 level E release, the DATS team found that several sites were not included in the TRF_BASIC_INFO table but have data in traffic monitoring tables. None of the sites from SPS-1, -2, -3, -4, -8, and -9 experiments and very few sites from other SPS experiments are included in the TRF_BASIC_INFO table. There were also several GPS sites missing from the TRF_BASIC_INFO table for the following sections: 223056, 283019, 283082, 480001, 481116, 481183, 483569, 483835, 483845, 489355, 271003, 271004, 273005, 273007, 273009, 273010, 273012, and 341003. Resolution of Problem/Situation: TRF_BASIC_INFO was intended for GPS sections only. It is Traffic Sheet 1, the cover sheet for data collected at sites in 1989 or earlier. All of the data in it for SPS projects, assuming that the data is actually being collected at the project site, can be found in SPS_ID. Similarly, if the data was collected at a GPS site, the data is already in INV_ID. Report Number: ERES-BW-107 Subject/IMS Table: Sites with questionable
pavement type in the table
TRF_MONITOR_BASIC_INFO. LTPP Analysis/Operations Situation: We found several sites in the IMS table TRF-MONITOR_BASIC_INFO using Q4, 2000 Level E release (11.2/NT 2.9), that have questionable pavement types reported in 1998. All these sites were rigid pavements for all the years except 1998 when the PAVEMENT_TYPE was changed to FLEXIBLE. In addition, the same PAVEMENT_STRUCT_NO was reported for all these sites: SN = 4.4. The EXPERIMENT_TYPE field for these sites was not changed in 1998. A list of sites in question was provided. These should be reviewed and be updated. Resolution of Problem/Situation: The Southern regional office has resolved the sections noted. As the ESAL calculation software is not currently available, ESAL computations were manually done and the upgrades were applied by an SQL script that was approved by the Technical Support Service Contractor. It should be noted that the ESAL estimates for only ANNUAL_ESAL_W4 and ESAL_VEHICLE_W4_MEAN were calculated. ANNUAL_ESAL_DATA and ESAL_VEHICLE_DATA_ MEAN were nulled as a large amount of resources are required for these computations. Report Number: ERES-BW-108 Subject/IMS Table: Sites with unreasonable
class distribution data in the table
TRF_MONITOR_VEHICLE_DISTRIB. LTPP Analysis/Operations Situation: While reviewing the IMS table TRF_MONITOR_VEHICLE_DISTRIB using IMS Q4, 2000 Level E release (11.2/NT 2.9), it was found that four sites have questionable class distribution for some years, as demonstrated in the attached table and figure. The identified records should be reviewed and either updated or deleted from the IMS table TRF_MONITOR_VEHICLE_DISTRIB. Resolution of Problem/Situation: Southern Region reports that data is not at Level E (Level D). The data fails the QC check for Volume_EST >= Volume_Classified. Recommended that this check be removed from QC process. Western Region purged erroneous data. Report Number: ERES-BW-109 Subject/IMS Table: Sites with questionable
axle load spectra in the table
TRF_MONITOR_AXLE_DISTRIB. LTPP Analysis/Operations Situation: While reviewing the data in the table TRF_MONITOR_AXLE_DISTRIB, using IMS Q4, 2000 Level E release (11.2/NT 2.9), we found several sites with extremely low axle load counts (less than 5 percent comparing to the other years) or highly atypical axle load distribution for some years. The identified records should be reviewed and either updated or deleted from IMS TRF_MONITOR_AXLE_DISTRIB table. Resolution of Problem/Situation: All suspect data has either been deleted or updated as recommended. Report Number: ERES-BW-132 Subject/IMS Table: Questionable or missing
traffic data in the LTPP database LTPP Analysis/Operations Situation: While reviewing the Level E traffic data, using Q1, 2000 LTPP database, release (10.4/NT 2.6), we found a number of sites with no traffic data or only AADT or AADT and class data available. Also, there are many sites for which axle load data are available in the database, but the data were evaluated as "unreliable" and were not used for projection. In some cases, axle load projections were made using questionable axle load data; projections for these sites are marked as "questionable". A list of sites with limited or not reliable traffic data was provided. Resolution of Problem/Situation: The missing data issue, at least to provide more information beyond AADT, is being addressed by the GPS data collection activity. The creation of axle distributions for those locations will be addressed but not for at least another year. As far as the reliability of the data, that can only be discussed with respect to the agencies' willingness/ability to provide Sheet 16s. For pre-2000 data, that just isn't going to happen because the sheet wasn't available prior to that date. With respect to the reasonableness of the data, the analysis software has most of the graphs needed to do the year-to-year trend evaluation and review. Report Number: ERES-BW-133 Subject/IMS Table: Recommendations for future
traffic data collection, management, and analysis.
LTPP Analysis/Operations Situation: As a part of the LTPP traffic data assessment and traffic projections project, several needs for the additional traffic data collection, management, and analysis were identified. A summary of the recommended future traffic data collection and analysis efforts was provided. Resolution of Problem/Situation: Most recommendations are being addressed through the traffic pooled fund study. Analysis recommendations are being addressed outside the feedback report process through the Data Analysis Strategic Plan. Report Number: LW-1 to LW-62 Subject/IMS Table: Initial traffic data
feedback and resolution packages prepared for State departments of
transportation (DOT). LTPP Analysis/Operations Situation: The Regional Offices received, for review, the Initial Traffic Data Feedback and Resolution Packages, prepared for the following state DOTs from the DATS traffic team: Alabama, Alaska, Alberta, Arizona, Arkansas, British Columbia, California, Colorado, Connecticut, Delaware, District of Columbia, Florida, Georgia, Hawaii, Idaho, Illinois, Indiana, Iowa, Kentucky, Louisiana, Maine, Manitoba, Maryland, Massachusetts, Michigan, Minnesota, Mississippi, Missouri, Montana, Nebraska, Nevada, New Brunswick, Newfoundland, New Hampshire, New Jersey, New Mexico, New York, North Carolina, North Dakota, Nova Scotia, Ohio, Oklahoma, Ontario, Oregon, Pennsylvania, Prince Edward Island, Puerto Rico, Quebec, Rhode Island, Saskatchewan, South Carolina, South Dakota, Tennessee, Texas, Utah, Vermont, Virginia, Washington, West Virginia, Wisconsin, Wyoming. Ultimately, the packages will be sent to the respective state DOT. However, before sending the packages to the state DOTs, examination of the packages by the Regional Offices is required. The DATS is to be informed of any changes required. Based on regional office comments, the DATS will update the packages and send them back to the Regional Offices. Once all the regional level corrections are done, the packages will be forwarded to the respective state DOTs. Resolution of Problem/Situation: Resolved as prescribed. Report Number: MACTEC-1 Subject/IMS Table: Location Information for New Mexico SPS-8 LTPP Analysis/Operations Situation: There appears to be a rather large Class 2/Class 5 classification problem for the March 1993 data by comparison with the remaining information as illustrated in the attached figures. Give serious consideration to purging all or part of the month and reprocessing the weight data through the traffic analysis software. Resolution of Problem/Situation: The Southern regional office has confirmed with the district that the route is the frontage road of IH-10, but they have a number for it, which is FR 1014. The SPS_ID table was updated to show the new route number and the route signing was changed to "other." Report Number: MACTEC-2 Subject/IMS Table: Unusual traffic data for 1998 for Ohio SPS-1 LTPP Analysis/Operations Situation: The vehicle distribution pattern for 1998 is inconsistent with the other years both in percentage and volume terms. Figures attached for reference. Investigate and retain with a comment in SHRP_INFO or other source accessible to a data user or reject. Resolution of Problem/Situation: After discussions with Ohio DOT, it was determined that the data submitted for this period had the lane number switched. Ohio re-submitted their data. The new data was reloaded using the proper lane and new purges were applied. NOTE: Ohio has closed this site numerous times over the past years. Some of these closures are for long periods. This translates into some low volumes for some years. Report Number: MACTEC-3 Subject/IMS Table: Unusual traffic data for Ohio SPS-2 LTPP Analysis/Operations Situation: The February and March 1998 data is irrational with 20 percent 4,000 lb Class9s. Figures were attached to illustrate problem and basis for selecting data to be deleted. Remove the data for 2/14 through 3/15/1998 unless use of an alternate classification scheme can be demonstrated. Resolution of Problem/Situation: Ohio re-submitted the data from this site. The new data was reloaded and new purges were applied. In addition to the data identified in this Data Analysis/Operations Feedback Report, more questionable data was identified and handled appropriately. Report Number: MACTEC-4 Subject/IMS Table: Unusual traffic data for Ohio SPS-8 and incorrect location. LTPP Analysis/Operations Situation: The volumes for this site are inconsistent with the observed volumes and the type of facility. This site is not on US 23 as per SPS_ID but on Norton-Waldo Road. GPS coordinates from site visit are 40° 25' 913" 83° 4' 488". The volumes/data submission for this site should be verified and notes made in SHRP_INFO or other database location to inform users as to why they were accepted. Resolution of Problem/Situation: The location information and GPS coordinates have been updated as suggested above. The feedback report is referring to North Bound Lane 1; this LTPP site is in the South Bound direction. Ohio re-submitted data from this site. The new data was loaded and purges applied. This site is affected by the closing of the US-23 South Bound lanes where the SPS-1 is located, causing traffic that wouldn't normally be traveling on the SPS-8 to be there for some periods of time. Report Number: MACTEC-5 Subject/IMS Table: Unusual traffic data for Colorado SPS-2 LTPP Analysis/Operations Situation: Classification data for 1995 and 1996 has distributions that are inconsistent with that of the weight data. Weight data for 1998 has a distinctly shifted GVW curve from other years. The shifts may be appropriate given the month-to-month cycling observed in previous years. The August 2000 weight data has only one vehicle type. Resolution of Problem/Situation:The Western regional office has reviewed the data in question and files have been purged as recommended by the agency. They verified that the actions taken resolved the issues in this feedback. The traffic analysis database and IMS have been updated. Report Number: MACTEC-6 Subject/IMS Table: Unusual traffic data for Kansas SPS-1 LTPP Analysis/Operations Situation: The traffic data for the SPS –1 in Kansas has an unusual shift in Class 9 GVW for 2001. There also appears to be an unusually low volume of weight data for Jul 1994. The other item is the difference in distributions between the earlier and later years of data. Resolution of Problem/Situation:There were two different periods that needed to be reviewed, one was for the year of 1994 and the second was for the year 2001. The 1994 data was showing unusually low volumes for weight data, specifically the data from April 25, 1994 and from June 30, 1994 to August 10, 1994 were considerably lower in volume then the rest of the year. These dates were purged with a comment of ATYPICAL PATTERN. The 2001 data showed some distinct signs of Lost/Drifted Calibration, the calibration drift was up to 25% in some periods. Weight data for the months of March through July were purged with a comment of MISCLASSIFICATION. Report Number: MACTEC-7 Subject/IMS Table: Unusual traffic data for Michigan SPS-2 LTPP Analysis/Operations Situation: There are some inconsistencies in the Michigan SPS-2 data. The November 1993 GVW data is inconsistent with all other months provided. The December data for the same year is also unusual as is April – July 1996 weight data. Steering axle information is provided as a secondary source of information as this site appears to have an average steering axle weight of Class9s of about 10,000 pounds. The Class 9 ESALs per vehicle graph has been included to illustrate the changing loading patterns that may be real or the effect of auto-calibration at the site. Volumes for weight data in June 1995 and classification data in July 1995 look light. There is a shift in Class9 steering axle weights in 2002 that brought them at least 454 kg (1,000 lb) lower than the historical average. Resolution of Problem/Situation: The feedback report is for the Michigan SPS-2 and for the years 1993, 1995, 1996 and 2002. Numerous graphs and reports generated by the software, and database SQLs have been reviewed to come to the final conclusions. We agree with most of the findings, and we are listing all the additional purges that we have applied to the data to help clean up this site. Report Number: MACTEC-8 Subject/IMS Table: Unusual traffic data for Kansas SPS-2 LTPP Analysis/Operations Situation: There appears to be a rather large Class 2/Class 5 classification problem for the March 1993 data by comparison with the remaining information as illustrated in the attached figures. Give serious consideration to purging all or part of the month and reprocessing the weight data through the traffic analysis software. Resolution of Problem/Situation: In reviewing the data identified in this feedback report, it appears that the Classification data for Vehicle Classes 2 and 5, collected during the month of March 1993, has a mis-classification problem. Since this month had only 1 week of Classification data, we have purged this data to remove it from further processing. Report Number: TJF-1 Subject/IMS Table: Possible error on table
trf_monitor_basic_info LTPP Analysis/Operations Situation: For site 482176, year 1995, field AADT_TRUCK_COMBO has a value of 350.4, when all other values are 30 to 70. Check value and correct if in error. Resolution of Problem/Situation: The Southern regional office reviewed the data and reported that there was nothing to indicate that the data was incorrect. No changes have been made Report Number: TSSC-35 Subject/IMS Table: Missing pre-1999 traffic
data. LTPP Analysis/Operations Situation: To preclude the regional offices having to load all of the data processed in the previous traffic software, the Technical Services Support Contractor undertook to recover the daily data by means of a three-step process involving extraction of old daily summary files for volume, classification and weight data. Not all files could be successfully extracted even after allowing for multiple attempts and corrections of invalid state codes and SHRP_IDs in the files. As a result a memo was prepared identifying those sites and years for which data will be missing from the IMS that previously existed. (Sept 4, 2002 - Incorporation of Data in Traffic Database to Support Existing IMS Traffic Data). Resolution of Problem/Situation: Not resolved. Report Number: TSSC-36 Subject/IMS Table: Invalid files in the
Central Traffic Database (CTDB) LTPP Analysis/Operations Situation: The Technical Services Support Contractor attempted to load all of the available SPS-1, -2, -5, -6 classification and weight files from the Central Traffic Database to validate the LTPP Traffic Analysis Software. A list was attached of the sites and years that failed to load. The files listed represent a 25% failure rate with over 90% of the problems being associated with the weight files. Among the reasons for failure are invalid record lengths, files that have not gone through the QC software, files with duplicate records for which the LTPP lane data cannot be identified and software termination without warning. Individual software failures were not investigated since they are not identified by the software as having a reason and would have to be investigated manually record by record. Each such failure is estimated to take at least a week of effort and would be better undertaken after the original files were reprocessed through the traffic QC software and all other sources of error ruled out. Resolution of Problem/Situation:As part of the December 2003 upload, the regional offices finished fixing and loading the sites listed in this report. Report Number: TSSC-37 Subject/IMS Table: Inconsistent values for SPS-1, -2, -5, -6 Traffic from disparate loading sources LTPP Analysis/Operations Situation: Data loading for SPS-1, -2, -5, and –6 sites has been done by 2 methods. Some through extraction of old daily summaries and others through direct loading from available files. As the convention is that no SPS section IDs are used in the traffic database, SPS section IDs have routinely been updated to the relevant project ID. Unfortunately in several cases this has not been possible since loading data using old files has sometimes come from multiple sections for the same year. In this case it would be expected that the total counts would be the same since the original data is the same. This is rarely a valid assumption. After review of the data the SPS projects on the attached list have multiple answers for the same year and the correct answer cannot be determined with certainty from the information available to the Technical Support Services Contractor. Data for these projects needs to be corrected so that valid loading information will exist for these sections. Resolution of Problem/Situation: As part of the December 2003 upload, the regional offices reviewed, corrected and loaded the data from sites listed in this report. Report Number: TSSC-38 Subject/IMS Table: Discrepancies between
SPS-3/-4 traffic and that of their linked GPS sections
LTPP Analysis/Operations Situation: Traffic data for an SPS-3 or –4 section should match the counts for the associated GPS section in any given year. In a comparison done using SPS_GPS_LINK to match data between the sections it was determined that this is not true in all instances with most problems involving data processed for the 1990-1992 time line. The discrepancy affects ESAL estimates and calls into question which data is correct for each site. From the information available, it is not possible to determine if the differences are due to incomplete processing for one group or the other, submission of data from two separate locations for sections that are on opposite sides of the road, SPS-3/-4 sections not in the same lane/direction as the linked section or different sources of information for the counts or GPS sections going out of study before the linked sections did. Data cannot be present in the traffic database for SPS-3/-4 sections that have a GPS link. Even after the GPS link goes out of study traffic data must continue to be loaded under the GPS ID to do trends evaluation of data. Resolution of Problem/Situation: As part of the May 2004 upload, the regional offices finished fixing and loading the sites listed in this report. Report Number: TSSC-39 Subject/IMS Table: Traffic for non-existent sections in the IMS. LTPP Analysis/Operations Situation: In trying to determine the reason sections were not represented in the IMS, it was determined that computations were being done for the following sections that are not in EXPERIMENT_SECTION: 124102, 014072, 276250, 276901, 296015, 399007, 049001, 049003, 049004, 049006, 059100, 059110. The data may be for rejected sections or simply mislabeled. Corrections, either deletion or renumbering should be made by the regional offices. The reason should also be provided so that the data may be flagged or removed from the Central Traffic Database and not distributed. Resolution of Problem/Situation: These sites are released or agency sites. Entries have been removed from the traffic database. Report Number: TSSC-40 Subject/IMS Table: Parsing of 4-card Classification Records with data beyond column 51 LTPP Analysis/Operations Situation: The original record format for submitting classification data to FHWA allowed agencies to use columns 52-80 for whatever information they wished to add. The original QC software and its subsequent conversion read the numbers in those columns as starting a new field every 2 columns. It has been determined that not all agencies used 2 columns but instead used 3 columns to define a field. Any agency data submitted using the 3-column format has been incorrectly interpreted by the Traffic QC software. This has led to an undetermined number of files for which erroneous volumes and conversions to TMG classification have been done. The errors may result in missing vehicles or excessive numbers of unclassifieds. Resolution of Problem/Situation: Not resolved. Report Number: TSSC-41 Subject/IMS Table: QC software conversion of C-cards to 4-cards LTPP Analysis/Operations Situation: While working on an unrelated data issue for the North Atlantic regional office, the issue of whether vehicle volumes are truncated when the conversion of the C-card format to 4-card format for classification data occurs. The C-card format uses 5-column fields for all volumes, while the 4-card uses 2 to 4 columns depending on the vehicles class. This problem is known to affect the counts of motorcycles for Puerto Rico. It is not known if there are any sites or agencies for which a vehicle class is present in numbers larger than anticipated in the design of the 4-card. Resolution of Problem/Situation: Not resolved. Report Number: TSSC-49 Subject/IMS Table: Traffic Data Files with large numbers of duplicates LTPP Analysis/Operations Situation: Use of Traffic Analysis QC software versions 1.6.1 or earlier when purging data files has resulted in a very large number of files with duplicates that can either confuse the user or have the potential to severely overestimate the loading estimates in the database. Resolution of Problem/Situation:Flat files were submitted from the regional offices to the Technical Support Service Contractor for edits. The edited flat files were then returned to the regional offices and changes were applied to the database. All sites (sites supplied in the feedback report plus additional sites) affected by this procedure were then reprocessed. Thorough spot-checking was done on the list of effected sites supplied in the feedback report and verified most of them. Report Number: TSSC-50 Subject/IMS Table: Class 7 Vehicles on WA 3813 having a leading quad axle (and no others) LTPP Analysis/Operations Situation: While investigating how the traffic analysis software version 1.3.1 binned and handled graphing for quad axles, it was discovered that the 2000 data for WA 3813 included 147,000+ Class 7 vehicles whose first axle was a quad (4-axle group) and had no other axles. Further queries produced a longer list of sites where more than 100 vehicles in a class for the data weighed had leading quad axles. Resolution of Problem/Situation: The Western regional office reviewed the data. Data from direction=3 and lane=1 were removed the database. The details of actions taken were provided. We consider this feedback report resolved. Report Number: TSSC-50a Subject/IMS Table: Class 7 Vehicles having a leading quad axle (and no others) LTPP Analysis/Operations Situation: While investigating how the traffic analysis software version 1.3.1 binned and handled graphing for quad axles, it was discovered that the 2000 data for WA 3813 included 147,000+ Class 7 vehicles whose first axle was a quad (4-axle group) and had no other axles. Further queries produced a longer list of sites where more than 100 vehicles in a class for the data weighed had leading quad axles. Resolution of Problem/Situation: Not resolved. Report Number: TSSC-51 Subject/IMS Table: Binning of quads in the traffic axle distribution tables LTPP Analysis/Operations Situation: The data for January 2004 in the table TRF_MONITOR_AXLE_DISTRIB has information on quad axles using two different binning criteria. For data processed with the old traffic analysis software, the bins are incremented in 1361 kg (3,000 pound) units. For data processed with the new traffic analysis software through version 1.3.1 (October 24, 2002 to May 11, 2004), the bins were incremented in 1814 kg (4,000 pound) units. Resolution of Problem/Situation: Version 1.4 of the software has the new binning rules incorporated. It was released May 7, 2004 and incorporated items 1 and 2. Item 3 has become part of the discussion material when data tables from the traffic database other than the TRF_MONITOR* tables are requested. Report Number: TSSC-52 Subject/IMS Table: Quad data irregularities for NJ 2000-2003 data LTPP Analysis/Operations Situation: Review of the quad data with 1814 kg (4,000 pound) increments revealed that for NJ data for 2000-2003 there are an unusual number of sites with quads that are either very heavy or incompatible with vehicle classes as defined by the TMG 13-bin system. Resolution of Problem/Situation: In reviewing the regional traffic database, we found the NJ 2000 to 2003 data to be reasonable for data retention in the database. It seems that, due to the fact that we are several iterations past the version of the database in which this feedback report was identified, we could not replicate the results found by the feddback report author. Report Number: TSSC-53 Subject/IMS Table: Quad data irregularities for Michigan data LTPP Analysis/Operations Situation: Review of the quad data with 1814 kg (4,000 pound) increments revealed that for Michigan data there are an unusual number of sites with quads that are very heavy. Determine the reasonableness of the data for retention in the database. If this outcome is consistent with Michigan specific trucks, the region should respond to this feedback report with information on typical truck GVW by class for Michigan. Resolution of Problem/Situation: In reviewing the regional traffic database, we found the Michigan data to be reasonable for data retention in the database. It seems that, due to the fact that we are several iterations past the version of the database in which this feedback report was identified, we could not replicate the results found by the feedback report author. Report Number: TSSC-54 Subject/IMS Table: "Large" numbers of very heavy quads in the traffic database LTPP Analysis/Operations Situation: Review of the data in the traffic database as a part of the quad axle binning investigation came up with several locations where the number of quad axles in the weight range was considered "large". A list of sites was provided for review and determination if the data is in fact valid. Resolution of Problem/Situation: When reviewing the outputs no numbers seemed to be extremely out of place, and the ones that were questionable were reviewed in more depth. What was found is the data with higher numbers in the QUAD_SUM fell under a pattern where a small number of days were submitted and when the calculations were performed by the Traffic Analysis software the numbers were greatly increased. This is based on a small number of days being used to generate annual numbers being inflated for averages of averages over the year. No changes were made. Report Number: TSSC-79 Subject/IMS Table: Incorrect translation of 6-digit classification code in LTAS LTPP Analysis/Operations Situation: It has been determined that at sites where cars were included in weight records and the data provided using the 6-digit Truck Weight Study format the cars were entered in the database as class 9s rather than Class 2s. As a result, very flaky GVW curves exist for some sites. For an undetermined number of sites, the data may have been mistakenly purged. Data needs to be reloaded for the site-years still in the database and consideration given to identifying other years at sites with the problem for which weight data may have been incorrectly purged. Resolution of Problem/Situation: Not resolved. |
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