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FHWA Home / Highways for LIFE / Technology Partnerships / Safety Product Performance Evaluations / Evaluation of The TAPCO Sequential Dynamic Curve Warning System

Evaluation of The TAPCO Sequential Dynamic Curve Warning System

PUBLICATION NO. FHWA-HIF-13-040
June 2013

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Technical Report Documentation Page

1. Report No.
FHWA-HIF-13-040

2. Government Accession No.
N/A

3. Recipient’s Catalog No.
N/A

4. Title and Subtitle
EVALUATION OF THE TAPCO SEQUENTIAL DYNAMIC CURVE WARNING SYSTEM

5. Report Date
June 2013

6. Performing Organization Code

7. Author(s)

Omar Smadi, Neal Hawkins, Shauna Hallmark, Skylar Knickerbocker

8. Performing Organization Report No.

Center for Transportation Research and Education
Iowa State University
2711 S. Loop Drive, Suite 4700
Ames, IA 50010

10. Work Unit No.

11. Contract or Grant No.
DTFH61-10-D-00025

12. Sponsoring Agency Name and Address
Federal Highway Administration
1200 New Jersey Avenue, SE
Washington, DC 20590

13. Type of Report and Period Covered
Interim Report

14. Sponsoring Agency Code

15. Supplementary Notes
Work performed as a subcontractor to SAIC, under the direction of Julie Zirlin, FHWA Contracting Officer's Technical Manager.

16. Abstract
Implementing safety countermeasures on rural horizontal curves to address speeding can improve the safety performance for those locations. State safety and traffic engineers are faced with making decisions on what type of technology to use and which sites to use the technology on in a fiscally constrained environment. The research conducted for this project will evaluate a Sequential Dynamic Curve Warning System (SDCWS) that could be an additional tool for these engineers to use either separately or in combination with other countermeasures to address horizontal curve locations with a history of safety concerns.

17. Key Words
horizontal curves—dynamic signs—SDCWS

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

9. Security Classif. (of this report)
Unclassified

20. Security Classif. (of this page)
Unclassified

21. No. of Pages
118

22. Price
N/A

Form DOT F 1700.7 (8-72)
Reproduction of completed page authorized
SI* (Modern Metric) Conversion Factors
APPROXIMATE CONVERSIONS TO SI UNITS APPROXIMATE CONVERSIONS FROM SI UNITS
Symbol When You Know Multiply By To Find Symbol Symbol When You Know Multiply By To Find Symbol
LENGTH LENGTH
in inches 25.4 millimeters mm mm millimeters 0.039 inches in
ft feet 0.305 meters m m meters 3.28 feet ft
yd yards 0.914 meters m m meters 1.09 yards yd
mi miles 1.61 kilometers km km kilometers 0.621 miles mi
AREA AREA
in2 square inches 645.2 square millimeters mm2 mm2 square millimeters 0.0016 square inches in2
ft2 square feet 0.093 square meters m2 m2 square meters 10.764 square feet ft2
yd2 square yards 0.836 square meters m2 m2 square meters 1.195 square yards yd2
ac acres 0.405 hectares ha ha hectares 2.47 acres ac2
mi2 square miles 2.59 square kilometers km2 km2 square kilometers 0.386 square miles mi2
VOLUME VOLUME
fl oz fluid ounces 29.57 milliliters ml mL milliliters 0.034 fluid ounces fl oz
gal gallons 3.785 liters L L liters 0.264 gallons gal
ft3 cubic feet 0.028 cubic meters m3 m3 cubic meters 35.314 cubic feet ft3
yd3 cubic yards 0.765 cubic meters m3 m3 cubic meters 1.307 cubic yard yd3
NOTE: Volumes greater than 1000 l shall be shown in m3
MASS MASS
oz ounces 28.35 grams g g grams 0.035 ounces oz
lb pounds 0.454 kilograms kg kg kilograms 2.202 pounds lb
T short tons
(2000 lb)
0.907 megagrams Mg Mg (or "t") megagrams
(or "metric ton")
1.103 short tons (2000 lb) T
TEMPERATURE (exact degrees) TEMPERATURE (exact degrees)
°F Fahrenheit 5(F–32)/9 or (F–32)/1.8 Celcius °C °C Celsius 1.8C +32 Fahrenheit °F
ILLUMINATION ILLUMINATION
fc foot–candles 10.76 lux lx lx lux 0.0929 foot–candles fc
fl foot–Lamberts 3.426 candela/m2 cd/m2 cd/m2 candela/m2 0.2919 foot–Lamberts fl
FORCE and PRESSURE or STRESS FORCE and PRESSURE or STRESS
lbf pounds 4.45 newtons N N newtons 0.225 poundforce lbf
lbf/in2 pound per square inch 6.89 kilopascals kPa kPa kilopascals 0.145 poundforce per square inch lbf/in2

*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)

Table of Contents

Introduction

Literature Review

Selection of Test Sites for SDCWS

Installation

Methodology for Speed Data Collection

Speed Analysis

Appendix B. Site Data Tables and Figures

  • Iowa Highway 144
  • Missouri Highway 221
  • Washington SR 7
  • Washington SR 9
  • Washington SR 203
  • Wisconsin Highway 20
  • Wisconsin Highway 67
  • Wisconsin Highway 213
  • Texas FM 109
  • Texas FM 407
  • Texas FM 530
  • Texas FM 1148

References

List of Figures

Figure 1 Photo: Northbound Interstate 5 DSFS systems in Oregon(22)
Figure 2 Photo. Southbound Interstate 5 DSFS systems in Oregon(22)
Figure 3 Photo. DSFS system in Norfolk. (23)
Figure 4 Photo. DSFS system in Bellevue, Washington (24)
Figure 5 Photo. Speed warning sign in the Sacramento River Canyon (26)
Figure 6 Photo. Comparison of curve warning sign (left) and speed feedback sign (right)(30)
Figure 7 Equation. True effect
Figure 9 Photo. Southbound Interstate 5 DSFS systems in Oregon.
Figure 8. Photo. Candidate curve site in Washington State
Figure 10. Chart. Example site visit speed data collection form
Figure 11. Photo. Example field report from initial visit
Figure 12 Map. Final test site locations
Figure 13 Photos. Installation of the SDCWS
Figure 14 Photo. SDCWS activation sequence
Figure 15 Diagram. Typical traffic counter placement
Figure 16 Photo. Iowa Highway 144 before data collection
Figure 17 Photo. Iowa Highway 144 1 month after data collection.
Figure 18 Photo. Iowa Highway 144 site layout
Figure 19 Chart. Iowa Highway 144 site information
Figure 20 Photo. Missouri Highway 221 before data collection
Figure 21 Photo. Missouri Highway 221 1 month after data collection
Figure 22 Photo. Missouri Highway 221 site layout
Figure 23 Chart. Missouri Highway 221 site information
Figure 24 Map. Washington State Route 9 before data collection
Figure 25 Map. Washington State Route 9 1 month after data collection.
Figure 26 Chart. Washington State Route 9 site information
Figure 27 Map. Washington State Route 203 before data collection
Figure 28 Map. Washington State Route 203 1 month after data collection
Figure 29 Chart. Washington State Route 203 site information.
Figure 30 Map. Washington State Route 7 before data collection.
Figure 31 Photo. Washington State Route 7 1 month after data collection
Figure 32 Chart. Washington State Route 7 site information.
Figure 33 Map. Wisconsin Highway 213 before data collection
Figure 34 Map. Wisconsin Highway 213 1 month after data collection.
Figure 35 Map. Wisconsin Highway 213 site layout.
Figure 36 Chart. Wisconsin Highway 213 site information.
Figure 37 Map. Wisconsin Highway 20 before data collection
Figure 38 Map. Wisconsin Highway 20 1 month after data collection.
Figure 39 Map. Wisconsin Highway 20 site layout
Figure 40 Chart. Wisconsin Highway 20 site information
Figure 41 Map. Wisconsin Highway 67 before data collection
Figure 42 Map. Wisconsin Highway 67 1 month after data collection
Figure 43 Map. Wisconsin Highway 67 site layout.
Figure 44 Chart. Wisconsin Highway 67 site information
Figure 45 Graph. Impact on vehicle speed - Iowa Hwy 144
Figure 46 Map and graphs. Location and change in percentile vehicle speed - Iowa Hwy 144
Figure 47 Graph. Impact on vehicle speed - Missouri Hwy 221
Figure 48 Map and graphs. Location and change in percentile vehicle speed - Missouri Hwy 221
Figure 49 Graph. Impact on vehicle speed - Washington SR 7
Figure 50 Map and graphs. Location and change in percentile vehicle speed - Washington SR
Figure 51 Graph. Impact on vehicle speed - Washington SR 9
Figure 52 Map and graphs. Location and change in percentile vehicle speed - Washington SR
Figure 53 Graph. Impact on vehicle speed - Washington SR 203
Figure 54 Map and graphs. Location and change in percentile vehicle speed - Washington SR 203
Figure 55 Graph. Impact on vehicle speed - Wisconsin Hwy 20
Figure 56 Map and graphs. Location and change in percentile vehicle speed - Wisconsin Hwy 20
Figure 57 Graph. Impact on vehicle speed - Wisconsin Hwy 67
Figure 58 Map and graphs. Location and change in percentile vehicle speed - Wisconsin Hwy 67
Figure 59 Graph. Impact on vehicle speed - Wisconsin Hwy 213
Figure 60 Map and graphs. Location and change in percentile vehicle speed - Wisconsin Hwy 213.
Figure 61 Graph. Impact on vehicle speed - Texas FM 109
Figure 62 Map and graphs. Location and change in percentile vehicle speed - Texas FM 109.
Figure 63 Graph. Impact on vehicle speed - Texas FM 407
Figure 64 Map and graphs. Location and change in percentile vehicle speed - Texas FM 407.
Figure 65 Graph. Impact on vehicle speed - Texas FM 530
Figure 66 Map and graphs. Location and change in percentile vehicle speed - Texas FM 530
Figure 67 Graph. Impact on vehicle speed - Texas FM 1148.
Figure 68 Map and graphs. Location and change in percentile vehicle speed - Texas FM 1148

List of Tables

Table 1 Advisory message for Interstate 5 dynamic speed-activated feedback sign system
Table 2 Final test sites by State
Table 3 Curve characteristics
Table 4 Installation dates.
Table 5 Summary of results at point of curvature after 1 month.
Table 6 Summary of results at center of curve after 1 month
Table 7 Schedule of activities, all sites
Table 8 Results for Iowa - Hwy 144 at PC
Table 9 Results for Iowa - Hwy 144 at CC.
Table 10 Speed Reduction for Iowa - Hwy 144
Table 11 Results for Missouri - Hwy 221 at PC
Table 12 Results for Missouri - Hwy 221 at CC.
Table 13 Speed reduction for Missouri - Hwy 221
Table 14 Results for Washington - SR 7 at PC
Table 15 Results for Washington - SR 7 at CC
Table 16 Speed reduction for Washington - SR 7
Table 17 Results for Washington - SR 9 at PC
Table 18 Results for Washington - SR 9 at CC.
Table 19 Speed reduction for Washington - SR 9
Table 20 Results for Washington - SR 203 at PC
Table 21 Results for Washington - SR 203 at CC
Table 22 Speed reduction for Washington - SR 203
Table 23 Results for Wisconsin - Hwy 20 at PC
Table 24 Results for Wisconsin - Hwy 20 at CC
Table 25 Speed reduction for Wisconsin - Hwy 20
Table 26 Results for Wisconsin - Hwy 67 at PC
Table 27 Results for Wisconsin - Hwy 67 at CC
Table 28 Speed Reduction for Wisconsin - Hwy 67
Table 29 Results for Wisconsin - Hwy 213 at PC
Table 30 Results for Wisconsin - Hwy 213 at CC.
Table 31 Speed reduction for Wisconsin - Hwy 213
Table 32 Results for Texas - FM 109 at PC
Table 33 Results for Texas - FM 109 at CC
Table 34 Results for Texas - FM 407 at PC
Table 35 Results for Texas - FM 407 at CC.
Table 36 Results for Texas - FM 530 at PC
Table 37 Results for Texas - FM 530 at CC
Table 38 Results for Texas - FM 1148 at PC
Table 39 Results for Texas - FM 1148 at CC

List of Abbreviations and Acronyms

AADT Annual average daily traffic
Caltrans California Department of Transportation
CC Center of curve
DOT

Department of Transportation

DSFS Dynamic speed feedback sign
FARS  Fatality Analysis Reporting System
GES General Estimates System
HSIS Highway Safety Information System
LIDAR Light detection and ranging
MUTCD

Manual on Uniform Traffic Control Devices

PC Point of curvature
SD Standard deviation
SDCWS Sequential Dynamic Curve Warning System
TE True effect
VPD Vehicles per day
Page last modified on June 23, 2016
Federal Highway Administration | 1200 New Jersey Avenue, SE | Washington, DC 20590 | 202-366-4000