REPORT 
This report is an archived publication and may contain dated technical, contact, and link information 

Publication Number:
FHWAHRT13048
Date: October 2013 
The following tables include the ttest results for all of the comparisons between and within sign sets that were discussed in chapter 4 (see task 7).
Table 19 and table 20 show the pvalues for the comparisons between sign sets for topic 1. Table 19 shows the comparisons between sign sets by movement from the starting lane to the desired destination.
Table 19. Topic 1 comparisons between sign sets by movement.
Sign Set Comparison  Movement 


Option to Exit 
Through to Exit 
Option to Through 

A to B 
0.6069 
0.0000 
0.2063 
A to C 
0.7191 
0.0386 
0.1448 
B to C 
0.3334 
0.0000 
0.7530 
Table 20 shows the comparisons between the option lane start and the through lane start within each sign set. The destination was the exit.
Table 20. Topic 1 comparisons within sign sets by movement.
Sign Set Comparison  pValue 

A to A 
0.0430 
B to B 
0.0000 
C to C 
0.4674 
Table 21 shows the comparisons between sign sets to determine the significance of both the arrow type (up versus down) and option lane arrow configuration (separated versus integrated).
Table 21. Topic 2 comparisons between sign sets.
Sign Set Comparison  pValue 

A to B 
0.1456 
A to C 
0.0000 
B to D 
0.0000 
C to D 
0.1385 
Table 22 and table 23 show the comparisons for topic 3. Table 22 shows the pvalues for the comparisons between sign sets for each question.
Table 22. Topic 3 comparisons between sign sets by question.
Sign Set Comparison  Question 1 
Question 2 
Question 3 

A to B 
0.0604 
0.0002 
0.0015 
A to C 
0.0036 
0.0017 
0.0014 
B to C 
0.0002 
0.7747 
0.0000 
Table 23 shows the pvalues for comparisons between questions 2 and 3.
Table 23. Topic 3 comparisons between Questions 2 and 3.
Sign Set Comparison  pValue 

A to A 
0.0000 
B to B 
0.0000 
C to C 
0.0000 
Table 24 shows the pvalues for comparisons between sign sets to determine the difference between multiline and hyphen separators for destination names.
Table 24. Topic 4 comparisons between sign sets.
Sign Set Comparison  pValue 

A to B 
0.0000 
C to D 
0.0000 
Table 25 shows the pvalues for the comparisons between the three sign sets examined in topic 5. Each sign used a different method to separate the two signed destinations: multiline, vertical line, or hyphen separators. Sign set A used a multiline separator; therefore, the top and bottom exits are separate entries.
Table 25. Topic 5 comparisons between sign sets.
Sign Set Comparison  pValue 

A (top exit) to A (bottom exit) 
0.0007 
A (top exit) to B 
0.0000 
A (bottom exit) to B 
0.0000 
B to C 
0.0000 
Table 26 shows the comparisons between the easy and hard task difficulty conditions for diagrammatic signs.
Table 26. Topic 6 comparisons between easy and hard conditions within sign sets.
Number of Lanes  pValue 

4 
0.0000 
5 
0.0004 
6 
0.0000 
7 
0.0000 
8 
0.0000 
9 
0.0000 
Table 27 through table 29 show the pvalues for the comparisons examined in topic 7. Table 27 shows the comparisons for the through movement condition.
Table 27. Topic 7 comparisons for through movement condition between sign sets.
Sign Set Comparison  pValue 

A to B 
0.0001 
A to C 
0.0447 
A to D 
0.0038 
A to E 
0.0190 
Table 28 shows the pvalues for select comparisons for the first (rightmost) exit movement. Since sign sets A2, B, and C all had the same percentage correct, sign set A2 was used to test for significance.
Table 28. Topic 7 comparisons for the first exit movement condition between sign sets.
Sign Set Comparison  pValue 

A to B2 
0.0582 
A2 to A 
0.3209 
A2 to B2 
0.4684 
Table 29 shows the pvalues for the comparisons between sign sets for the second exit movement condition.
Table 29. Topic 7 comparisons for second exit movement condition between sign sets.
Sign Set Comparison  pValue 

A to A2 
0.0000 
A to B 
0.0000 
A to B2 
0.0000 
A to C 
0.0000 
A2 to B 
0.0832 
A2 to B2 
0.0491 
A2 to C 
0.0001 
B to B2 
0.7655 
B to C 
0.0000 
B2 to C 
0.0000 
Topics: research, safety Keywords: research, safety, Complex Interchanges, Interchanges, Signage, Driver Behavior TRT Terms: research, Safety and security, Safety, Transportation safety Updated: 04/09/2014
