Office of Operations
21st Century Operations Using 21st Century Technologies

Application of Travel Time Data and Statistics to Travel Time Reliability Analyses: Handbook and Support Materials


Over the past decade, the collection and dissemination of travel time data and summary statistics has grown exponentially. The increased availability of these data has led to the adoption of new monitoring and measuring activities by States and metropolitan planning organizations to evaluate the performance of the transportation system. Travel time data is available in numerous forms. This report provides a guide and supporting material for working with these data in the development of travel time reliability performance assessment and reporting.


This document is disseminated under the sponsorship of the U.S. Department of Transportation in the interest of information exchange. The U.S. Government assumes no liability for the use of the information contained in this document.

The U.S. Government does not endorse products or manufacturers. Trademarks or manufacturers’ names appear in this document only because they are considered essential to the objective of the document. They are included for informational purposes only and are not intended to reflect a preference, approval, or endorsement of any one product or entity.

Non-Binding Contents

Except for the statutes and regulations cited, the contents of this document do not have the force and effect of law and are not meant to bind the States or the public in any way. This document is intended only to provide information regarding existing requirements under the law or agency policies.

Quality Assurance Statement

The Federal Highway Administration (FHWA) provides high-quality information to serve Government, industry, and the public in a manner that promotes public understanding. Standards and policies are used to ensure and maximize the quality, objectivity, utility, and integrity of its information. The FHWA periodically reviews quality issues and adjusts its programs and processes to ensure continuous quality improvement.

Technical Report Documentation Page

1. Report No.


2. Government Accession No.

3. Recipient’s Catalog No.

4. Title and Subtitle

Application of Travel Time Data and Statistics to Travel Time Reliability Analyses Handbook and Support Materials

5. Report Date

July 2023

6. Performing Organization Code

7. Author(s)

Richard Margiotta, Richard Ge, and Moggan Motamed

8. Performing Organization Report No.

9. Performing Organization Name and Address

Cambridge Systematics Inc.
3 Bethesda Metro Center, Suite 1200
Bethesda, MD 20814

10. Work Unit No. (TRAIS)

11. Contract or Grant No.


12. Sponsoring Agency Name and Address

U.S. Department of Transportation
Federal Highway Administration
Office of Operations
1200 New Jersey Avenue, SE
Washington, DC 20590

13. Type of Report and Period Covered

Final Report; August 2017–June 2021

14. Sponsoring Agency Code


15. Supplementary Notes

Doug Laird and Rich Taylor served as the Task Order Contracting Officer’s Representatives.

16. Abstract

This project developed a handbook and supporting materials for working with travel time data in the development of travel time reliability performance assessment and reporting. The intent of the handbook is twofold: to provide practitioners with the ability to understand the differences in reliability measures derived from the different data sources and to document the steps needed to turn high-resolution travel time data into reliability performance measures. The handbook covers several topics including data sources for reliability; data processing methods for reliability; and creating and comparing reliability measures, highlighting differences and similarities in the use of data from different sources. A case study was conducted that compared reliability measures developed from different data sources using different processing methods.

17. Key Words

Travel time, reliability, performance, assessment, data, data collection, third-party providers, speed, volume

18. Distribution Statement

No restrictions. This document is available to the public through the National Technical Information Service, Springfield, VA 22161.

19. Security Classif. (of this report)


20. Security Classif. (of this page)


21. No of Pages


22. Price

Form DOT F 1700.7 (8-72)
Reproduction of completed pages authorized

SI (Modern Metric)

Approximate Conversions to SI Units
Symbol When You Know Multiply By To Find Symbol
in inches 25.4 millimeters mm
ft feet 0.305 meters m
yd yards 0.914 meters m
mi miles 1.61 kilometers km
in2 square inches 645.2 square millimeters mm2
ft2 square feet 0.093 square meters m2
yd2 square yard 0.836 square meters m2
ac acres 0.405 hectares ha
mi2 square miles 2.59 square kilometers km2
fl oz fluid ounces 29.57 milliliters mL
gal gallons 3.785 liters L
ft3 cubic feet 0.028 cubic meters m3
yd3 cubic yards 0.765 cubic meters m3
NOTE: volumes greater than 1000 L shall be shown in m3
oz ounces 28.35 grams g
lb pounds 0.454 kilograms kg
T short tons (2000 lb) 0.907 megagrams (or "metric ton") Mg (or "t")
Temperature (exact degrees)
°F Fahrenheit 5 (F-32)/9 or (F-32)/1.8 Celsius °C
fc foot-candles 10.76 lux lx
fl foot-Lamberts 3.426 candela/m2 cd/m2
Force and Pressure or Stress
lbf poundforce 4.45 newtons N
lbf/in2 poundforce per square inch 6.89 kilopascals kPa

Conversion Factors

Approximate Conversions from SI Units
Symbol When You Know Multiply By To Find Symbol
mm millimeters 0.039 inches in
m meters 3.28 feet ft
m meters 1.09 yards yd
km kilometers 0.621 miles mi
mm2 square millimeters 0.0016 square inches in2
m2 square meters 10.764 square feet ft2
m2 square meters 1.195 square yards yd2
ha hectares 2.47 acres ac
km2 square kilometers 0.386 square miles mi2
mL milliliters 0.034 fluid ounces fl oz
L liters 0.264 gallons gal
m3 cubic meters 35.314 cubic feet ft3
m3 cubic meters 1.307 cubic yards yd3
g grams 0.035 ounces oz
kg kilograms 2.202 pounds lb
Mg (or "t") megagrams (or "metric ton") 1.103 short tons (2000 lb) T
Temperature (exact degrees)
°C Celsius 1.8C+32 Fahrenheit °F
lx lux 0.0929 foot-candles fc
cd/m2 candela/m2 0.2919 foot-Lamberts fl
Force and Pressure or Stress
N newtons 02.225 poundforce lbf
kPa kilopascals 0.145 poundforce per square inch lbf/in2

Note: SI is the symbol for the International System of Units. Appropriate rounding should be made to comply with Section 4 of ASTM E380. (Revised March 2003)