Contents
LIST OF ACRONYMS 4
Executive Summary 10
1. Introduction 13
2. Methods 16
2.1. Participants 16
2.1.1. Recruitment 16
2.1.2. Demographics 17
2.2. Experimental Design 19
2.3. Commercial Products Used as the Framework for the Custom Applications 20
2.3.1. iZup from Illume 20
2.3.2. Cellcontrol from obdEdge, LLC 21
2.4. Adaptation as Research Tool 21
2.5. Overrides 22
2.6. Objective and Subjective Data 23
2.7. Data Analysis 23
2.7.1. Dataset 23
2.7.2. Data files 24
3. Results 27
3.1. Phone use Behavior 27
3.1.1. Speed at which participants placed outgoing calls 27
3.1.2. Unanswered Incoming Calls 32
3.1.3. Speed at which participants sent SMS 34
3.1.4. Call duration while driving 35
3.1.5. What were the overrides use patterns? 40
3.1.6. What is the effect of cell phone filter/blockers on driver performance? (subjective) 44
3.1.7. Were there lasting effects? 46
3.2. Technical Performance and User Acceptance 48
3.2.1. What was the technical effectiveness/reliability of the cell phone filter/blockers? 48
3.2.2. How did drivers feel about the cell phone filter/blockers? 50
3.2.3. Did drivers "Game" the system, and if so how? 55
3.2.4. General Participant Opinions 56
3.3. Organizational Impacts 58
3.3.1. What were the management opinions of the experience with implementing a cell phone filter/blocker system? 58
3.3.2. What was the effect of the cell phone filter/blockers on work productivity? 59
3.3.3. What are the costs of savings or losses due to the cell phone filter/blocker implementation? 60
4. Conclusions 66
4.1. Phone Use Behavior 66
4.1.1. Speed at which participants placed outgoing calls 66
4.1.2. Unanswered Incoming Calls 66
4.1.3. Speed at which participants sent SMS 67
4.1.4. Call duration while driving 67
4.1.5. What is the effect of cell phone filter/blockers on driver performance? (subjective) 67
4.1.6. Were there lasting effects? 68
4.2. Technical Performance and User Acceptance 68
4.2.1. What was the technical effectiveness/reliability of the cell phone filter/blockers? 68
4.2.2. How did drivers feel about the cell phone filter/blockers? 68
4.2.3. Did drivers "game" the system, and if so how? 69
4.2.4. General Participant Opinions 69
4.3. Organizational Impacts 69
4.3.1. What were the management opinions of the experience with implementing a cell phone filter/blocker system? 69
4.3.2. What was the effect of the cell phone filter/blockers on work productivity? 70
4.3.3. What are the costs of savings or losses due to cell phone filter/blocker implementation? 70
5. Lessons Learned 71
5.1. Organizational Buy-in 71
5.2. Installation 71
5.3. Battery Life 71
5.4. Passenger Versus Driver 72
5.5. Override Difficulty 72
5.6. Personal Phones 72
6. Considerations for Future Research 73
6.1. Custom Applications 73
6.1.1. Software-Only 73
6.1.2. Hardware/Software 73
6.2. Overrides 73
6.3. Only Block Visual Manual Phone Tasks 74
6.4. Data Verification 74
6.5. Passenger Versus Driver Log 74
7. References 75
8. Appendix A. Application Provider Overview 77
8.1. Software-Only Applications 77
8.2. Hardware/Software Combination Applications 79
8.3. Summary of Commercially Available Applications 80
9. Appendix B. Recruitment Script 81
10. Appendix C. Cell Phone Filtering/Blocking Field Test Post-experience Questionnaire 82
11. Appendix D. Management Questions (in addition to previous questionnaire questions) 86
12. Appendix E. Battery Life Readings with and without Custom Cell Phone/Filter Blocker Software Application Installed. 87
Table 1. Gender breakdown of participants in the final dataset 18
Table 2. Age group breakdown of participants in the final dataset 18
Table 3. All outgoing calls for participants who received the Software-Only application 27
Table 4. All outgoing calls for participants who received the Software-Only application split by blocking period 28
Table 5. All outgoing calls for participants who received the Hardware/Software application 30
Table 6. All outgoing calls for participants who received the Hardware/Software application split by blocking period 31
Table 7. All incoming calls for participants who received the Software-Only application 32
Table 8. All incoming calls with known speeds for participants receiving the Software-Only application split by data collection period 33
Table 9. All incoming calls for participants who received the Hardware/Software application 33
Table 10. All incoming calls with known speeds for participants receiving the Hardware/Software application split by data collection period 34
Table 11. All outgoing SMS for participants who received the Software-Only application 35
Table 12. Mean durations of non-zero speed outgoing calls for participants receiving the Software-Only application 35
Table 13. Mean durations of non-zero speed incoming calls for participants receiving the Software-Only application 37
Table 14. Mean durations of non-zero speed outgoing calls for participants receiving the Hardware/Software application 38
Table 15. Mean durations of non-zero speed incoming calls for participants receiving the Hardware/Software application 39
Table 16. Information on blocking overrides and the activities performed during these overrides for participants who received the Software-Only application (data from Blocking period only). 40
Table 17. Information on blocking overrides and the activities performed during these overrides for participants who received the Hardware/Software application (data from Blocking period only). 42
Table 18. Questionnaire responses to Likert-scale questions Q14, Q15, Q22 44
Table 19. Questionnaire responses to Likert-scale questions Q21 and Q23 46
Table 20. Questionnaire responses to Q6, "What was your favorite aspect of the blocking technology?" 50
Table 21. Questionnaire responses to Q7, "What was your least favorite aspect of the blocking technology?" 50
Table 22. Questionnaire responses to Q8, "What would you change about the blocking technology in order to make it more beneficial to you?" 51
Table 23. Questionnaire responses to Likert-scale questions Q16, Q17, Q18, Q19 52
Table 24. Questionnaire responses to Likert-scale questions Q24, Q25, Q26 56
Table 25. Questionnaire responses to Likert-scale questions MQ4, MQ5 58
Table 26. Battery life as reported by participant before and after cell phone filter/blocker software was uninstalled from the participants' phones 87
Figure 1. Map of Michigan Department of Transportation regions 19
Figure 2. Average calls per day split by data collection period, for the Software-Only application 28
Figure 3. Mean speeds at which outgoing calls were placed split by data collection period for participants who received the Software-Only application. For this plot, all calls initiated at zero-speed were removed from the data. 29
Figure 4. All calls per day split by data collection period for the Hardware/Software application 30
Figure 5. Mean speeds at which outgoing calls were placed split by data collection period for participants who received the Hardware/Software application. For this plot, all calls initiated at zero-speed were removed from the data. 32
Figure 6. Boxplots of outgoing call durations for participants receiving the Software-Only application 36
Figure 7. Boxplots of incoming call durations for participants receiving the Software-Only application 37
Figure 8. Boxplots of outgoing call durations for participants receiving the Hardware/Software application 38
Figure 9. Boxplots of incoming call durations for participants receiving the Hardware/ Software application 39
Figure 10. Frequency of overrides (overrides per day) for participants receiving the Software-Only application 41
Figure 11. Frequency of overrides (overrides per day) for participants receiving the Hardware/Software application 43
Figure 12. Distribution of responses to Q22, "I think having this blocking software on my phone increased my driving safety." 45
Figure 13. Distribution of responses to Q21, "I find that since my experience with the cell phone blocking software, I use my phone less while driving in my personal vehicle than I did previously." 47
Figure 14. Distribution of responses to Q23, "I would like to have this software on my personal phone." 48
Figure 15. Distribution of responses to Q16, "I found the operation of the software easy to understand." 53
Figure 16. Distribution of responses to Q17, "During the blocking phase when the software was active, I like that I get an indication that I am receiving an incoming call even though I cannot answer it." 54
Figure 17. Distribution of responses to Q18, "The lag time after I finished driving during which the blocking was still active was not a problem during my participation." 55
Figure 18. Distribution of responses to Q25, "I think MDOT should adopt this software for all its employees." 57
Figure 19. Distribution of responses to Q5: "On average, over the last 6 weeks, how much time did you spend driving as a portion of each 8-hour workday?" 60