Traffic Data Quality Analysis. James Sturrock, PE, PTOE, FHWA Resource Center Operations Team

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1 Traffic Analysis James Sturrock, PE, PTOE, FHWA Resource Center Operations Team

2 Source Material Traffic Measurement Seven DEADLY Misconceptions about Information Quality Traffic Analysis Toolbox

3 Traffic Data Recommendations

4 Air Quality Conformity Analysis Models

5 Transportation Planning Applications 1 Accuracy 2 Completeness Validity Timeliness Typical Coverage Air Quality Conformity Analysis VMT by vehicle class, hour and functional classification VMT by hour and vehicle classification (Distribution of VMT by speed) 10% mph At a given location 50% - Two weeks per month, 24 hours At a given location 25% - one week per month, 24 hours Up to 15% failure rate - 48-hour Up to 10% failure rate - permanent count stations Up to 15% failure rate - 48-hour Up to 10% failure rate - permanent Within three years of model validation year Within three years of model validation year 75% Freeways/Express ways 25% principal and minor arterials 10% collectors 75% Freeways/Express ways 25% principal and minor arterials 10% collectors

6 Traffic Demand Forecasting Models

7 Transportation Planning Applications 1 Accuracy 2 Completeness Validity Timeliness Typical Coverage Daily traffic volumes Freeways: 7% Principal Arterials: 15% Minor Arterials: 20% Collectors: 25% At a given location 25% - 12 consecutive hours out of 48-hour count Up to 15% failure rate - 48-hour Up to 10% failure rate - permanent count stations Within three years of model validation year 55-60% of freeway 25% of principal arterials 15% of minor arterials 10-15% of collectors Standard demand forecasting for Long Range Planning Hourly traffic volumes Freeways: 7% Principal Arterials: 15% Minor Arterials: 20% Collectors: 25% At a given location 25% - 12 consecutive hours out of 48-hour count Up to 15% failure rate - 48-hour Up to 10% failure rate - permanent Within three years of model validation year 55-60% of freeway 25% of principal arterials 15% of minor arterials 10-15% of collectors Vehicle occupancy 10-15% At a given location 25% - 12 consecutive hours out of 48-hour count Up to 15% failure rate - 48-hour Up to 10% failure rate - permanent Within three years of model validation year 1-5% of total population (from surveys)

8 Transportation Planning Applications 1 Accuracy 2 Completeness Validity Timeliness Typical Coverage Percentage single unit trucks Percentage combination trucks 7-10% 3-5% Minimum 25% - 12 consecutive hours out of 48-hour count Minimum 50% - 12 consecutive hours out of 24-hour count Up to 15% failure rate - 48-hour Up to 10% failure rate - permanent Within three years of model validation year 55-60% of freeway 25% of principal arterials 15% of minor arterials 10-15% of collectors Standard demand forecasting for Long Range Planning Transit boardings and alightings by station and/or stop 15-20% 7-10% (Transit Planning) 75% of annual data collection Up to 15% failure rate - 48-hour Up to 10% failure rate - permanent Within three years of model validation year 100% of rail boardings 10% of bus route ridership from screen line data Transit vehicle speeds by analysis time period 15-20% <5% - one peak and one off-peak route Up to 15% failure rate - 48-hour Up to 10% failure rate - permanent Within three years of model validation year 100%

9 Transportation Planning Applications 1 Accuracy 2 Completeness Validity Timeliness Typical Coverage Standard demand forecasting for Long Range Planning Free Flow link speeds Congested link speeds 15-20% At V/C < 1.0, 10 mph At V/C >1.0, 2.5 mph % validity for instrumented floating car data collection % validity for instrumented floating car data collection % validity for instrumented floating car data collection % validity for instrumented floating car data collection Within three years of model validation year Within three years of model validation year 100% Freeway 100% Major arterial % Collectors 10% Local road 100% Freeway 100% Major arterial % Collectors 10% Local road

10 Traffic Simulation Models

11 Transportation Planning Applications 1 Accuracy 2 Completeness Validity Timeliness Typical Coverage Traffic volumes by minute or subminute 2.50% 90% validity Up to 15% failure rate - portable traffic Within one year of study 100% of study area Traffic simulation Turning movements by 15 minutes 5-10% error rate 95% validity - manual traffic 0% failure - manual traffic Within one year of study 100% of study area Free Flow link speeds 5.00% % validity for instrumented floating car data collection % validity for instrumented floating car data collection Within one year of study 100% of study area

12 Transportation Planning Applications 1 Accuracy 2 Completeness Validity Timeliness Typical Coverage Congested link speeds and delay statistics 2.50% % validity for instrumented floating car data collection % validity for instrumented floating car data collection Within one year of study 100% of study area Traffic simulation Queue length 95% validity - manual count 100% validity - manual count Within one year of study 100% of study area

13 Congestion Management

14 Transportation Planning Applications 1 Accuracy 2 Completeness Validity Timeliness Typical Coverage Corridor-level vehicle speeds and/or travel times by hour 5% % validity for instrumented floating car data collection % validity for instrumented floating car data collection Within six months of study 100% of study area Congestion management Origin-Destination travel times by hour 5% % validity for instrumented floating car data collection % validity for instrumented floating car data collection Within six months of study 1-5% of study area (from surveys)

15 Highway Performance Monitoring System

16 Transportation Planning Applications 1 Accuracy 2 Completeness Validity Timeliness Typical Coverage AADT 5-10% Urban Interstate 10% Other urban 8% Rural Interstate 10% Other Rural Mean Absolute Error 80% continuous count data 70-80% for portable machine (24- /48-hour ) Up to 15% failure rate - 48-hour Up to 10% failure rate - permanent count stations Data three years old or less 55-60% of freeway 25% of principal arterials 15% of minor arterials 10-15% of collectors Highway Performance Monitoring System K factor D factor 5-10% RMSE (relative) 1% RMSE (relative) 80% continuous count data 50% for portable machine (24- /48-hour ) Up to 15% failure rate - 48-hour Up to 10% failure rate - permanent count stations Data three years old or less 55-60% of freeway 25% of principal arterials 15% of minor arterials 10-15% of collectors Percent combination and single-unit trucks - Daily 20% RMSE 15% RMSE 80% continuous count data 50% for portable machine (24- /48-hour ) Up to 15% failure rate - 48-hour Up to 10% failure rate - permanent count stations Data three years old or less 55-60% of freeway 25% of principal arterials 15% of minor arterials 10-15% of collectors

17 Transportation Planning Applications 1 Accuracy 2 Completeness Validity Timeliness Typical Coverage Highway Performance Monitoring System VMT Percent combination and single-unit trucks - Peak 5-10% RMSE Downward bias 25% RMSE 20% RMSE 80% continuous count data 50% for portable machine (24-/48-hour ) 80% continuous count data 50% for portable machine Up to 15% failure rate - 48-hour Up to 10% failure rate - permanent count stations Up to 15% failure rate - 48-hour Up to 10% failure rate - permanent count stations Data one year old or less Data three years old or less 55-60% of freeway 25% of principal arterials 15% of minor arterials 10-15% of collectors 55-60% of freeway 25% of principal arterials 15% of minor arterials 10-15% of collectors

18 Monthly Count Station Volume Reports

19 Transportation Planning Applications 1 Accuracy 2 Completeness Validity Timeliness Typical Coverage Hourly volumes for seven consecutive days each month 2% RMSE 100% valid data 100% valid data required Data one month old or less <1% of total roadway Monthly count station volume reports AVC stations: Hourly volumes by vehicle class category 15% Single-Unit Truck Classification Error 100% valid data 100% valid data required Data one month old or less <1% of total roadway

20 Generalized Coverage Discussion Traffic Planning Application Typical Coverage (Generalized from above) Air Quality Conformity Analysis Traffic Demand Models Traffic Simulation Models Congestion Management HPMS Monthly Count Sta. Report 75% of Freeways, 25% of Arterials, 10% of Collectors 60% of Freeways, 25%of Arterials, 15% of Collectors 100% of Freeways, Arterials,& Collect 100% of Freeways, Arterials, &Collect 60% of Freeways, 25% of Arterials, 15% of Collectors <1% of Total Roadway Milage

21 There are seven potentially fatal misconceptions about information quality that can hamper an information quality initiative. Worse yet, if these misconceptions are strongly held, they will hamper business effectiveness (best case) or result in business failure. The seven deadly misconceptions are:

22 The seven deadly misconceptions are: 1. "Information quality is data cleansing" 2. "Information quality is data assessment" 3. "Conformance to business rules is the same as data accuracy" 4. Accuracy"; and its counterpoint: Information quality is fitness for purpose" 5. "Information quality problems are caused by information producers; and its corollary: Information quality is produced by an information quality group" 6. "Information quality problems can be edited out by implementing business rules" 7. "Information quality is too expensive"

23 Congestion Patterns are Dynamic Portland DTA Study Example Speed : Space-Time diagram with trajectories

24 Travel Times Are Dynamic Portland DTA Study Example Change in travel time for vehicles traveling entire route between 4PM and 6PM Original network

25 Changes Influence Traveler Behavior Portland DTA Study Example Change in travel time for vehicles traveling entire route between 4PM and 6PM Comparison of original network to alternative network

26 Traffic Modeling Calibration Reference Traffic Analysis Toolbox Determine MOEs for calibration early in process to frame data needs Utilize Statistical Methods for determining appropriate number of runs utilizing two MOEs Calibrate to both global and local MOEs Calibrate, Calibrate, Calibrate!

27 Source Material Traffic Measurement Seven DEADLY Misconceptions about Information Quality Traffic Analysis Toolbox

28 Thank you