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Chapter two reviewed research and trade literature on rel- evant principles and specific practices relating to carrier operational efficiency and safety. An additional method for obtaining information for this study was project surveys. Two similar survey forms were used for two different respon- dent groups. Most important was a survey of current CMV fleet safety managers. The safety-manager survey asked respon- dents their opinions on safety effects of operational practices, what practices they used, and their ratings of their effectiveness. Of secondary importance, but still of interest, was a survey of other experts in motor carrier safety. This survey form addressed the same general topics, but was limited to opinions because the respondents were not current practitioners. The two survey forms are provided in Appendix A. This chapter describes the survey approach and specific methods, and pro- vides principal results for each respondent group. Results for the two respondent groups are presented separately because of their different perspectives on the problem, and because the two forms differed somewhat in their questioning approaches and in specific content. A general caveat regarding most of the survey responses is that they represent subjective responses to subjective questions. A few questions were objective (e.g., questions asking safety managers whether or not they use a particular safety management practice), but most called for subjective judgments by respondents. Another caveat is that both sam- ples must be regarded as convenience samples of interested, knowledgeable individuals, not as representative samples of larger populations. Conceptually, both the safety-manager and other-expert populations are amorphous and are not cap- tured by any list. In addition, the safety-manager popula- tion is extremely large (in the hundreds of thousands in the United States), diverse, and problematic from the sampling perspective. OVERVIEW OF SURVEY APPROACH, ANALYSIS, AND INTERPRETATION Sampling Approach The conceptual population for the safety-manager survey was North American motor carrier (truck and bus) safety managers. This population is somewhat amorphous, as there is no con- sistent definition or criterion for âcarrier safety manager.â Also, there is no central potential respondent list that could be used as the basis for systematic sampling or as a source for accurate respondent contact information likely to result in a satisfactory survey return rate. The safety-manager sample consisted of individuals par- ticipating in trade associations or national meetings relating to motor carrier safety. The e-mail addresses of these individ- uals were known to the project team, or paper survey forms were distributed directly to them in trade association meetings. The sample is presumed here to be strongly biased toward orga- nizations and individuals with more experience, past success, safety sophistication, and safety conscientiousness than the overall population. Those returning the survey (whose responses are presented here) are the respondents. Just as the sample space was likely a biased slice of the population, the sample was likely a biased slice of the sample space. That is because in most surveys, those responding tend to be more committed and interested in the topic than those not responding. Moreover, they tend to be more educated and verbal (Walonick 2010). Both sources of bias almost certainly operated, and operated strongly, in the present safety-manager survey and, perhaps to a lesser extent, in the other-expert survey. A larger study focusing on the survey per se likely could do a better job of capturing the larger population, increas- ing the size and representativeness of the sample space, and obtaining a higher survey response rate. Study resources did not permit a more extensive, rigorous, and layered subject sampling approach. The obtained sample, even if represent- ing a skewed sample of the most knowledgeable and safety- conscious respondents, still provided valuable information, however, for the following reasons: â¢ It tapped the views and practices of industry leaders. â¢ It provided information on the subjectsâ relative opinions on the various operational risk factors and practices presented. â¢ It provided contacts for follow-up interviews with safety managers regarding the practices of safety-active companies. Data Analysis and Interpretation There were three general types of questions on the surveys: questions about respondent opinions, questions about specific carrier practices (safety managers only), and questions about CHAPTER THREE SURVEY METHODS AND RESULTS 30
31 respondents themselves and their organizations. Opinion questions were subjective and called for subjective, judg- mental responses, mostly in the form of Likert scale ratings. These responses should not be misinterpreted as objective facts. Questions about specific carrier practices asked for yesâno answers and, when the answer was âyes,â asked for an effectiveness rating on a Likert scale. These were on the safety-manager survey forms only. Questions about the respondents themselves (e.g., years of experience) were also objective. All of the caveats discussed earlier regarding sam- ple representativeness apply to all questions on both forms. Thus, none of the survey results on either form can be gen- eralized to larger respondent groups or populations such as âNorth American carrier safety managersâ or âexperts in motor carrier safety.â The value of the survey results is not based on representativeness to larger populations, but rather on the respondentsâ answers to specific questions relative to other, similar questions. For example, which operational factors are most associated (positively or negatively) with risk? Which specific operational practices were rated as most safety-effective? Non-Use of Response Percentages Per CTBSSP policy, the survey results tables in this chap- ter, and survey results cited elsewhere in this report, do not include results percentages. Instead, raw numbers are cited (e.g., â42 of 51 respondents . . .â). This practice reduces the likelihood that survey results will be misinterpreted or incorrectly cited as representing larger respondent pop- ulations. Readers may generate their own percentages, but they should not be reported as being representative of larger groups. Likert Scale Means Likert scales are numeric rating scales, often with five choices numbered from 1 to 5. Likert scales usually have word descrip- tors for each choice, or âanchorâ choices at the ends and per- haps the middle. Two different Likert scales were used in the project surveys: â¢ A seven-point scale relating driving situations and oper- ational practices to crash risk. Choices ranged from âreduces fleet safety (â3)â to âimproves fleet safety (+3).â â¢ A five-point scale rating the safety effectiveness of car- rier operational practices. Choices ranged from âhighly ineffective (1)â to âhighly effective (5).â Some pairs of questions were intentionally constructed to present oppo- site strategies. Results are provided here in the form of respondent counts for each choice, along with the weighted arithmetic mean of all choices. Median responses are also provided for the seven- point scale items. TRBâs online survey service provided these statistics automatically in survey reports. For paper surveys, the survey statistics were obtained from Excel spreadsheets used to enter and reduce the data. MOTOR CARRIER SAFETY-MANAGER SURVEY METHODS This section describes methods specific to the safety-manager surveys. Safety managers were the respondent group of great- est interest for the study. These individuals have company titles such as safety manager, safety director, director of compli- ance, and vice president for safety (and/or compliance). A few have titles relating to operations. The respondent pool (sam- ple space) consisted of individuals participating in national industry groups supporting safety, or who had attended safety meetings and whose contact information was available to the project team. As discussed in the previous section, the respondent pool may be characterized as representing safety- conscious carrier safety or operational managers who are will- ing to participate in such research. All of the sampling and data analysis issues discussed previously apply to the safety- manager survey. Questionnaire Design and Content The safety-manager survey questionnaire consisted of the fol- lowing general sections: â¢ A brief statement of the study and survey purpose, with a confidentiality assurance. â¢ Two related five-choice questions on general factors affecting safety and crash risk (used in the paper form only). These questions were omitted from the survey form to help increase the response rate. â¢ Fifteen driving situations or operational practices, each rated on a â3-to-+3 Likert scale (â3, â2, â1, 0, +1, +2, +3) for effect on fleet safety. Negative values were for âreduces fleet safety,â whereas positive values were for âimproves fleet safety.â One item (item 9) was omitted from the bus version because it was not applicable to bus operations. â¢ Eleven carrier operational practices and tools, with a two- part answer for each: â Yesâno for whether the practice was used by the man- agerâs fleet; and â If yes, a 1â5 Likert scale to rate the practiceâs safety effectiveness. One item (item 21) was omitted from the bus version because it was not applicable to bus operations. â¢ A single four-choice question on the general relation between carrier efficiency and safety. â¢ An open-response question asking what operational efficiency or practice contributed most to fleet safety. â¢ An open-response question asking for any other comments.
â¢ Four questions on respondentâs professional experi- ence and fleet characteristics. â¢ A space to provide an optional e-mail address to which to send the project report PDF. Questionnaire Distribution and Analysis Two commercial motor vehicle trade associations, the Truck- load Carriers Association and the Bus Industry Safety Coun- cil, assisted the study by distributing paper survey forms (both for this project and MC-22) at national meetings. A third asso- ciation, the NPTC, assisted the effort by e-mailing the online survey solicitation to its Safety Council members, with the councilâs endorsement. Paper surveys were formatted on a single front-and-back sheet where answer choices were to be circled or penciled in. At the Truckload Carriers Association meeting, approximately 100 survey forms (for each of the two projects) were dis- tributed, and 24 were returned. Two other truck forms were obtained through personal contacts. At the Bus Industry Safety Council meeting, approximately 50 forms were distributed, and 30 were returned. At the latter meeting, attendees included a significant proportion of non-safety managers (e.g., govern- ment officials, trade association officials, vendors, and consul- tants) for whom the survey was not intended. The exact number of carrier safety managers in the room is not known. An additional effort to obtain safety-manager respon- dents was made using TRBâs online survey service. The online survey had the same content as the paper survey, except for the omission of the first two questions relating to general crash-risk factors. These two questions were somewhat wordy âthought questions,â requiring more time for response than others on the survey. They were omitted from the online version to streamline the survey and per- haps increase response rates. E-mail requests were sent to 130 respondents believed to be current motor carrier safety managers based on their business cards and contact information gathered at various recent motor carrier safety conferences. An additional solici- tation was sent from an NPTC official to NPTC Safety Coun- cil members. Twenty-five people took the online version of the survey. This brought the total safety-manager survey sample to 79 (24 + 30 + 25). Paper survey answers were entered into an Excel spread- sheet for analysis. Online survey tabulations were generated and added to the Excel sheet totals. The earlier experience suggests that both methods are viable. Handing out paper surveys at trade association meet- ings with the support of the organizers likely yields a higher return than does e-mail solicitation. Carrier officials are the targets of a lot of product marketing and other promotions, and thus may tend to be wary of responding to external e-mails in general. Potential respondents may have confidentiality concerns, even if confidentiality statements are prominent in 32 survey materials. Walonick (2010) provides a more extensive discussion of the difficulties of obtaining survey data from various respondent groups. According to one report (cited in McQuire 2010), only about half of e-mails are opened. This highlights the difficulty of obtaining high response rates from e-mailed surveys. In spite of the challenges of obtaining a robust survey sam- ple and the acknowledged unrepresentativeness of the sample in relation to all safety managers, the 79 responses did provide sufficient data for analysis as well as many useful comments. In addition, a number of respondents volunteered for follow- up structured interviews, described here. Follow-Up Structured Interviews The last question of the MC-23 (Driver Selection Tests and Measurements; Knipling et al. 2001) safety-manager survey form asked respondents if they would be interested in partici- pating in a paid follow-up interview to discuss innovative fleet practices. The question included the assurance, âResponses will be confidential; no interviewees or carriers will be iden- tified unless desired.â The key purpose of the interviews was to gather information and opinions for project case study write-ups (see chapter four). If respondents did volunteer, and had a relatively large number of âyesâ responses under carrier practices for both surveys (MC-22 and MC-23), they were contacted to schedule an interview (covering both MC-22 and MC-23 topics). Altogether, 20 respondents were contacted, usually both by e-mail and by phone. Apparently, most had second thoughts because only 10 agreed to participate. These 10, however, provided substantial information on carrier oper- ational practices relating to safety. One other carrier was added through personal contact. Thus, 11 case studies are provided in chapter four. MOTOR CARRIER SAFETY-MANAGER SURVEY RESULTS Factors Affecting Safety and Crash Risk Questions 1 and 2 addressed factors affecting safety and crash risk. These were also the first two questions of the MC-23 sur- vey, as the two questions were pertinent to both studies. The same five choices were presented in each. Question 1 asked for the respondentâs choice of up to two factors having the greatest effect, whereas Question 2 asked for the one factor with the least effect. Table 6 presents responses. As expected, choices for the two opposite questions (great- est and least) were more or less inversely related. Driver- related choices (a) and (b) were regarded as having the greatest effect on crash risk. The vehicle-related choice (c) received the fewest âmostâ votes, whereas (d) âRoadway characteristics and traffic conditions,â received the greatest number of âleastâ votes. Thus, both (c) and (d) could be regarded as âlosers.â Ironically, perhaps, choice (d) has the greatest relevance to the current study, because many operational transport efficien-
33 (1) Factors Affecting Safety and Crash Risk: Consider the entire fleet of North American commercial vehicles (trucks and buses). Across all these drivers and vehicles, which factors have the greatest association with crash risk? Pick up to two of the factors below which, in your opinion, have the greatest association with crash risk. (2) In your opinion, which one factor has the least association with crash risk? (1) Most (2) Least (a) Enduring/long-term driver traits; e.g., age, physical abilities, medical conditions, personality, behavioral history. 31 5 (b) Temporary driver states; e.g., moods, daily circadian rhythms, effects of recent sleep, effects of recent food & fluids, effects of environmental conditions in cab, etc. 32 4 (c) Vehicle characteristics (e.g., configuration, safety equipment, load) & mechanical condition (e.g., brakes, tires). 7 12 (d) Roadway characteristics & traffic conditions; e.g., undivided vs. divided highways, construction zones, traffic density, speed limits, lane restrictions, etc. 10 14 (e) Weather and roadway surface conditions; e.g., wet vs. dry, road surface friction, visibility, wind, etc. 9 8 Total Responses: 89 43 TABLE 6 SAFETY-MANAGER RESPONSES RELATING TO FACTORS AFFECTING SAFETY AND CRASH RISK FIGURE 6 Factors affecting crash risk. 10 15 20 25 30 35 0 5 Enduring Driver Traits Temporary Driver States Vehicle Characteristics Roadway & Traffic Weather & Surface Condition R es po nd en t V o te s (2 Ea ch ) cies are related to roadway and routing choices. Other choices may also be relevant to specific operational practices. Figure 6 shows the âmostâ vote tallies graphically. Driving Situations and Operational Practices Possibly Affecting Fleet Safety Questions 3 to 17 presented 16 driving situations and opera- tional practices, preceded by the following general instructions: The following are driving situations or carrier operational prac- tices which may reduce, not affect, or improve fleet safety. Assign each situation or practice a negative value if it decreases safety, zero if it does not affect safety, or a positive value if it improves safety. Choose one number for each. Consecutive items may rep- resent alternative or even opposing safety strategies. A seven-point Likert rating scale was used for responses, ranging from â3 (reduces fleet safety) through 0 (no effect on safety) to +3 (improves fleet safety). âXâ was given as a choice for âno opinion/not sure.â Table 7 provides the 15 items, the number of ratings for each of the eight choices (â3, â2, â1, 0, +1, +2, +3, X) plus the total number of responses (N), the median (Md) and the arithmetic average (Avg), also known as the mean. Median ratings are provided along with mean rat- ings because of the large number of choices (7) and because extreme choices might shift means unduly. Question 9 was omitted from the bus version of the survey because it was not considered relevant to bus transport, owing to the rela- tive inflexibility of bus schedules. Thus, the number of responses to this question was lower and applied only to truck transport.
Four practices received the highest mean ratings: (4) reduc- ing loading and unloading delays, (5) increasing routing effi- ciency, (6) maximizing travel on Interstates, and (11) avoiding adverse weather. Closely following were (10) avoiding urban rush hours and (13) assigning familiar routes to drivers. The practice receiving the highest negative rating was (7) maxi- mizing travel on low-speed roads, followed by (9) maximizing night driving. The highest rating variabilities were seen on the two items relating to truck size (14 and 15). Both received votes for all seven Likert scale ratings, suggesting a great deal of disagreement on this issue. Figure 7 shows graphically the 16 items in ascending order by mean rating. Operational Practices and Tools Used by Fleets Questions 18 to 28 presented 11 carrier practices and first asked respondents to state whether or not they regularly used the prac- tice (yes or no). Respondents answering âyesâ on a question were then to rate the effectiveness of the practice on a five-point Likert scale. The specific instructions were as follows: 34 TABLE 7 SAFETY-MANAGER RATINGS OF DRIVING SITUATIONS AND OPERATIONAL PRACTICES For each of the operational practices below, please indicate yes or no whether your organization uses the practice. If yes, rate its overall safety effectiveness using the 1â5 scale provided. Circle your answer. If no, leave the ratings blank. The five Likert scale choices were: 1. Highly Ineffective; 2. Ineffective; 3. Not Sure/Neutral; 4. Effective; and 5. Highly Effective. Table 8 provides the number of respondents who reported using each practice. Table 9 shows the effectiveness ratings given by users of the practice. Statistics provided include the number for each Likert scale choice, the total number of responses (N), and the weighted arithmetic average or mean of responses (Avg.). Averages are rounded to the nearest tenth. Respondents used Driving Situation/Operational Practice: -3 -2 -1 0 +1 +2 +3 X N Md Avg. (3) Reduce empty backhauls (deadheads) 0 2 5 35 14 12 3 7 78 0 +0.5 (4) Reduce loading/unloading delays 0 0 1 8 18 25 19 7 78 +2 +1.8 (5) Increase routing efficiency using GPS navigation aids and/or truck routing software 0 1 0 3 20 37 13 3 77 +2 +1.8 (6) Maximize travel on Interstates and other freeways 0 0 2 4 18 34 17 2 77 +2 +1.8 (7) Maximize travel on low-speed roads (e.g., two-lane local roads) 10 21 30 4 5 3 2 2 77 -1 -1.1 (8) Maximize day driving to avoid driver fatigue & other nighttime risks 0 1 3 8 25 23 17 1 78 +2 +1.5 (9) Maximize night driving to avoid daytime 3 7 16 4 14 4 0 1 49 0 -0.4 traffic [truck data only] (10) Avoid urban rush hours and other heavy traffic situations 1 1 0 4 21 27 19 3 76 +2 +1.7 (11) Avoid adverse weather and slick roads 1 1 2 2 16 33 23 0 78 +2 +1.8 (12) Avoid construction zones 1 1 1 4 32 29 9 1 78 +1 +1.4 (13) Assign familiar routes to drivers when possible 0 2 2 7 15 29 22 0 77 +2 +1.7 (14) Use fewer, larger trucks (e.g., multi- trailer trucks) when possible 1 4 8 25 13 10 8 8 77 0 +0.6 (15) Use more, smaller trucks (e.g., single- unit trucks) when possible 3 2 9 32 14 8 1 9 78 0 +0.2 (16) Use onboard computers 1 0 6 17 18 18 11 7 78 +1 +1.1 (17) Use mobile communication systems 3 5 9 16 15 15 9 6 78 +1 +0.6 Grand Mean: +1.0 Avg. = Arithmetic average (mean); Md = Median (middle); N = Number of respondents.
35 0 0.5 1 1.5 2 â1.5 â1 â0.5M ea n â 3 to + 3 Ra tin g FIGURE 7 Fifteen driving situations and operational practices, rank-ordered by safety-manager mean safety rating. TABLE 8 SAFETY-MANAGER RESPONDENT USE OF OPERATIONAL PRACTICE/TOOL Operational Practice/Tool: Yes No N (18) Preventive maintenance (PM) schedule and record for each vehicle 77 2 79 (19) Preventive maintenance software or spreadsheets 62 16 78 (20) Use brokers or other services to reduce empty backhauls (deadheads) 30 47 77 (21) Charge extra fees to customers for excessive loading/unloading delays 34 16 50 (22) Require drivers to complete a trip plan prior to trip. 24 53 77 (23) Use general GPS navigation/routing systems or services 42 34 76 (24) Use truck-specific navigation/routing systems or services 29 48 77 (25) Provide Ã¬EZ Passâ transponder and/or reimbursement of toll charges to drivers/owner-operators 66 12 78 (26) Use higher capacity vehicles (e.g., twin trailers, LCVs) when possible 17 60 77 (27) Use onboard computers 41 33 74 (28) Use mobile communications 58 20 78 N = number of respondents. Rating or Statistic:
an average of 6.1 of the 11 practices listed. The most fre- quently used were PM schedules and records for each vehicle, providing âEZ Passâ and toll reimbursements to drivers, and using PM software or spreadsheets. The least frequent practice was the use of higher-capacity vehicles. Other practices used by a minority of respondents were requiring drivers to com- plete trip plans and using truck-specific GPS navigation aids. Almost all 11 of the practices received favorable ratings of safety effectiveness. Only item (20), âUsing brokers or other services to reduce empty backhauls,â received a neutral mean 36 rating (3.0 on the 1-to-5 scale). The 10 other practices received mean ratings in a relatively narrow range between 3.4 and 4.3. Item 18, âPreventive maintenance schedule and record for each vehicle,â received the highest overall rating (4.3). Additional Questions Question 29 asked respondents about the general relationship between carrier efficiency and safety. Table 10 presents the question stem, response choices, and number for each. Rating or Statistic Operational Practice/Tool 1 2 3 4 5 N Avg. (18) Preventive maintenance schedule and record for each vehicle 4 1 2 33 35 75 4.3 (19) Preventive maintenance software or spreadsheets 2 0 11 32 14 59 3.9 (20) Use brokers or other services to reduce empty backhauls (deadheads) 1 7 14 8 1 31 3.0 (21) Charge extra fees to customers for excessive loading/unloading delays 2 1 14 18 0 35 3.4 (22) Require drivers to complete a trip plan prior to trip 0 2 4 14 5 25 3.9 (23) Use general GPS navigation/routing systems or services 1 2 10 24 4 41 3.7 (24) Use truck-specific navigation/routing systems or services 1 1 5 17 5 29 3.8 (25) Provide âEZ Passâ transponder and/or reimbursement of toll charges to drivers/OOs 1 0 22 26 14 63 3.8 (26) Use higher capacity vehicles (e.g., twin trailers, LCVs) when possible 0 1 3 10 3 17 3.9 (27) Use onboard computers 1 1 9 17 9 37 3.9 (28) Use mobile communications 0 3 22 23 8 56 3.6 Grand Mean: 3.7 TABLE 9 SAFETY-MANAGER LIKERT SCALE RATINGS OF EFFECTIVENESS OF OPERATIONAL PRACTICE/TOOL TABLE 10 GENERAL RELATION BETWEEN CARRIER EFFICIENCY AND SAFETY FOR SAFETY MANAGERS (29) What is the relationship between carrier efficiency and safety? Circle the letter of the statement you most agree with. N (a) Highly efficient carriers tend also to be more safe than other carriers. 63 (b) Carrier efficiency and carrier safety are largely unrelated to each other. 8 (c) Highly efficient carriers tend to be less safe than other carriers. 2 (d) Donât know/no general opinion. 4 Total: 77
37 A strong 63 of 77 respondents believed that highly efficient carriers also tended to be safe carriers. Only 2 of 77 respon- dents thought the association was negative. Question 30 asked respondents to write in the operational efficiency or other practice contributing most to fleet safety. Because this was an open-response item, responses varied and not all respondents answered the question. Many of the responses did not relate specifically to report topics. Others did relate directly or partially to carrier efficiencies addressed in this report. Here are the responses: â¢ Preventative maintenance and/or pre- posttrip inspec- tions [eight respondents] â¢ Driver training from a new hire to refresher training with a trainer riding along to observe and comment; âcom- prehensiveâ driver training; other training-related [five respondents] â¢ Onboard computers [three respondents] â¢ Incentive/safety bonus program [two respondents] â¢ You must develop a safety culture from the top down. You must be willing to make investments in technology to promote safety. â¢ Executive and management involved in all levels of safety and compliance â¢ We are a fleet of all owner-operators. Communication is the key to our efficiency and assists us in being a safe and efficient heavy haul company. â¢ Conducting a thorough pre- and post-trip inspection â¢ Reduction of speed â¢ Participation of the drivers in programs aimed at safety â¢ Driver debriefing and communication â¢ Insistence on daily management monitoring of pre- and post-trip inspections â¢ Onboard camera system â¢ Help locations with route development to ensure HOS compliance, and onboard e-logs. Also, quarterly driversâ meetings and Smith System Advanced Driver Training â¢ Using technology but the driver remains in control of the vehicle â¢ Effective, engaged management on-site, interaction with drivers and showing true caring for their well-being goes far with our drivers, more than electronics or computers. â¢ Accountability for safety â¢ Governed truck speeds â¢ No one practice but a culture â¢ Driver and maintenance staff input â¢ Speed reduction and driver wellness programs â¢ Ten-point safety and productivity incentive plan with quarterly review and cash incentive for each driver â¢ Keeping up with driver logsârest times and keeping drivers on similar shifts, especially regarding time off- duty â¢ Operational efficiency means âwell run,â not âget the load there on time or else.â â¢ Prudent use of fleet and deadhead moves Question 31 asked for other comments regarding carrier efficiencies or other practices affecting fleet safety positively or negatively. These comments were similar to those noted above. Here are the responses: â¢ Training, training, more training â¢ Insistence on pre-trip inspections before loading to include on-board knuckle boom crane [for off-loading and field loading of heavy cargo] pre-trip â¢ Inefficiencies of shipper/receivers in the loading and unloading process have the most negative effect on safety for our drivers. â¢ Efficiency and safety must be used in conjunction, and not considered âstand-aloneâ initiatives. â¢ Our biggest challenge is with our customers and sup- pliers. There is ignorance or apathy toward an efficient loading or unloading process. â¢ Electronic logs may be able to help with logbook falsi- fication, which would help with the safety issue. â¢ Comprehensive driver wellness program, detailed audit of HOS have had very positive impact on safety. â¢ Ongoing training, the daily presence of safety person- nel advocating safety â¢ Need a safety person present in operations to provide pos- itive safety influence daily â¢ Drivers appreciate efforts to reduce fatigue and improve time driving. â¢ Strong oversight of operations â¢ Periodic retraining of drivers, regular safety meetings, follow-up on PMs, meet with mechanics each week and go over work orders for past and current week â¢ Driver training and supervision â¢ Long-term core values should drive decisions, not short- term âfirefighting;â focus on prevention, not reaction. â¢ Central operations environment helps control the excess movement of fleet. â¢ Efficient scheduling and routing contributes to safe operations. Information About Respondents and Their Fleets Safety managers were also asked two questions about their professional experience and two questions about their fleetâs characteristics. Question 32 asked their years of experience as a safety manager or human resource manager, and Ques- tion 33 asked their total years of experience in commercial truck or bus operations. Table 11 provides summary statistics of their answers. Altogether, the 79 safety-manager respondents claimed 989 yearsâ experience as safety managers and 1,821 years total experience in CMV transport. As a group, they are highly experienced. Question 34 asked respondents to state the approximate number of power units (i.e., tractors or trucks) currently in
their fleets. Table 12 provides summary statistics of their answers. There are no definitive population statistics to compare with the previously cited respondent individual and fleet sta- tistics. Nevertheless, it is clear that survey respondents gener- ally were more experienced than most individuals with motor carrier safety management responsibilities, and that their fleets were generally much larger than average. This reflects the trend of larger fleets being overrepresented at virtually all national and regional safety conferences, and as active mem- bers of national and state truck and bus transport organizations. Question 35 asked respondents to select the truck or bus operation type that best characterized their fleet. The num- bers of responses in each category are listed in Table 13. Although the question asked for âtheâ best characterization, many bus safety managers selected two choices (âgâ and âhâ in Table 13). Therefore, that dual selection is listed later as a separate choice. OTHER-EXPERT SURVEY METHODS The secondary project survey was of other experts in motor carrier safety. These individuals were primarily professional associates of the principal project investigators. They were known personally or through their jobs or other professional activities. They included professionals in government, indus- try trade associations, other industry roles (e.g., safety con- sulting), and research. Many of these individuals are actively involved in other TRB truck and bus safety activities. Even though these individuals are highly knowledgeable, they are regarded as secondary respondents because they are (by defi- nition) not currently carrier practitioners. Their survey forms 38 TABLE 11 SUMMARY STATISTICS ON PROFESSIONAL EXPERIENCE OF SAFETY-MANAGER RESPONDENTS included opinion items, but no items on their operational practices, because they are not so involved. The data from this other-expert survey were of interest, although, as it (1) gauges expert opinion on questions, (2) points toward areas perhaps deserving more consideration, and (3) is a way of identifying ongoing research relating to project topics. Questionnaire Design and Content The other-expert survey questionnaire was similar to that for safety managers. It consisted of the following general sections: â¢ A brief statement of the study and survey purpose, with a confidentiality assurance; â¢ Two related five-choice questions on general factors affecting safety and crash risk (used on paper form only); â¢ 16 driving situations or operational practices, each rated on a â3-to-+3 Likert scale (â3, â2, â1, 0, +1, +2, +3) for effect on fleet safety; â¢ A multiple choice question on the general relationship between carrier efficiency and safety; â¢ An open âcommentsâ space; and â¢ Two questions on respondentâs years of motor carrier safety-related experience and on specific types of posi- tions held. Questionnaire Distribution and Analysis The other-expert survey was administered only online through TRBâs online survey service. The survey solicitation was sent by means of e-mail to 134 individuals, with a second e-mail reminder sent several weeks later. A total of 32 online surveys Statistic Question Range Median Mean StDev (32) Number of years experience as carrier Safety Manager or Human Resource Manager 2 to 45 10 13.2 9.1 (33) Total years experience in commercial truck/bus operations 5 to 62 22 24.0 12.6 Note: StDev = standard deviation. Statistic Range Median Mean SD Question (34) Approximate number of power units currently in fleet 14 to 15,000 112.5 866 2,201 TABLE 12 SUMMARY STATISTICS ON SAFETY-MANAGER RESPONDENT FLEET SIZE
39 TABLE 13 SAFETY-MANAGER RESPONDENTSâ FLEET OPERATION TYPES were completed (24%). Survey results were tabulated by the reports program. OTHER-EXPERT SURVEY RESULTS Factors Affecting Safety and Crash Risk Questions 1 and 2 addressed factors affecting safety and crash risk. The same five choices were presented in each. Question 1 asked for the respondentâs choice of up to two factors hav- ing the greatest effect, whereas Question 2 asked for the one factor with the least effect. Table 14 presents responses. As expected, choices for the two opposite questions (greatest and least) were more or less inversely related. Driver-related choices (a) and (b) were regarded as having the greatest effect on crash risk, whereas vehicle-related choice (c) was regarded as having the least. Choice (d) has the greatest overall rele- vance to the current study, because many operational transport efficiencies are related to roadway and routing choices. Other choices may also be relevant to specific operational practices. This respondent group considered temporary driver states (b) to be the strongest factor affecting crash risk. Roadway characteristics and traffic conditions, the choice most relevant to the current study, was third in the âmostâ voting and fourth in the âleastâ voting. Thus, relative to safety managers, other experts considered choice (d) to be relatively more important. Driving Situations and Operational Practices Possibly Affecting Fleet Safety Questions 3 to 18 were preceded by the following general instructions: The following are driving situations or carrier operational prac- tices which may reduce, not affect, or improve fleet safety. Assign each situation or practice a negative value if it decreases safety, zero if it does not affect safety, or a positive value if it improves safety. Choose one number for each. Consecutive items may rep- resent alternative or even opposing safety strategies. A seven-point Likert rating scale was used for responses, ranging from â3 (reduces fleet safety) through 0 (no effect on safety) to +3 (improves fleet safety). âXâ was given as a choice for âno opinion/not sure.â Table 15 provides the 16 items, the number of ratings for each of the eight choices (â3, â2, â1, 0, +1, +2, +3, X), as well as the total number of Operation Type No. Safety Managers Total (N): 73 (a) For hire: long haul/truckload 21 (b) For hire: long haul/less-than-truckload (LTL) 2 (c) For hire: local/short haul (most trips < 100 miles) 2 (d) Private industry: long haul 6 (e) Private industry: local/short haul (< 100 miles) 10 (f) Passenger carrier: scheduled service 4 (g) Passenger carrier: charter 15 (g+h) Passenger carrier: both scheduled service and charter 10 (h) âOtherâ (mostly variations of above types) 3 (1) Factors Affecting Safety and Crash Risk: Consider the entire fleet of North American commercial vehicles (trucks and buses). Across all these drivers and vehicles, which factors have the greatest association with crash risk? Pick up to two of the factors below which, in your opinion, have the greatest association with crash risk. (2) In your opinion, which one factor has the least association with crash risk? (1) Most (2) Least (a) Enduring/long-term driver traits; e.g., age, physical abilities, medical conditions, personality, behavioral history 14 7 (b) Temporary driver states; e.g., moods, daily circadian rhythms, effects of recent sleep, effects of recent food & fluids, effects of environmental conditions in cab, etc. 25 0 (c) Vehicle characteristics (e.g., configuration, safety equipment, load) & mechanical condition (e.g., brakes, tires) 7 12 (d) Roadway characteristics & traffic conditions; e.g., undivided vs. divided highways, construction zones, traffic density, speed limits, lane restrictions, etc. 10 3 (e) Weather and roadway surface conditions; e.g., wet vs. dry, road surface friction, visibility, wind, etc. 2 9 Total Responses: 58 31 TABLE 14 OTHER-EXPERT RESPONSES RELATING TO FACTORS AFFECTING SAFETY AND CRASH RISK
responses (N), the median (Md) and the arithmetic average (Avg.), also known as the mean. Median ratings are pro- vided along with mean ratings because of the large number of choices (seven), and because extreme choices might shift means unduly. Note also that Questions 17 (on driver teams) and 18 (on fuel economy monitoring) had no corresponding questions on the safety-manager version of the survey. The practices with the highest mean ratings for these respon- dents were preventive maintenance (item 3, +2.1), maximizing travel on Interstates and freeways (item 7, +1.7), and assigning familiar routes to drivers (item 14, +1.6). Those rated overall as detrimental to safety included travel on low-speed road- ways (item 8, â1.6) and night driving (item 10, â0.7). Notice 40 the spread of answers for Questions 15 and 16 regarding truck size, indicating a wide range of opinions. Additional Questions Question 20 asked respondents about the general relation- ship between carrier efficiency and safety. Table 16 pre- sents the question stem, response choices, and number for each. A strong majority of respondents (26 of 31) believed that efficient carriers were also safe carriers. Question 19 asked respondents to write in other comments regarding carrier efficiencies or other practices that affect fleet Driving Situation/Operational Practice: â3 â2 â1 0 +1 +2 +3 N Md Avg. (3) Perform regular vehicle preventive maintenance 0 0 0 0 10 8 13 31 +2 +2.1 (4) Use brokers or other services to reduce empty backhauls (deadheads) 2 0 4 19 4 2 0 29 0 -0.1 (5) Reduce loading/unloading delays 0 2 0 2 15 5 7 31 +1 +1.4 (6) Increase routing efficiency using GPS navigation aids and/or truck routing software and websites 0 0 0 7 18 3 3 31 +1 +1.1 (7) Maximize travel on Interstates & other freeways 0 0 0 2 12 9 8 31 +2 +1.7 (8) Maximize travel on low-speed roads (e.g., two-lane local roads) 6 11 10 3 1 0 0 31 -2 -1.6 (9) Maximize day driving to avoid driver fatigue & other nighttime risks 0 1 1 5 11 11 2 31 +1 +1.2 (10) Maximize night driving to avoid daytime traffic 1 7 12 7 2 2 0 31 -1 -0.7 (11) Avoid urban rush hours and other heavy traffic situations 0 0 3 4 14 5 5 31 +1 +1.2 (12) Avoid adverse weather and slick roads 1 0 1 3 12 11 3 31 +1 +1.3 (13) Avoid construction zones 0 1 0 4 14 8 4 32 +1 +1.3 (14) Assign familiar routes to drivers when possible 0 0 0 2 13 10 6 31 +2 +1.6 (15) Use fewer, larger trucks (e.g., multi- trailer trucks) when possible 2 1 4 9 7 5 3 31 0 +0.4 (16) Use more, smaller trucks (e.g., single- unit trucks) when possible 3 2 6 13 6 0 1 31 0 -0.3 (17) Maximize use of driver teams for long hauls 1 0 1 7 18 2 2 31 +1 +0.8 (18) Monitor fuel economy for individual drivers and provide feedback 0 0 1 12 13 4 1 31 +1 +0.7 8.0+:naeMdnarG Avg. = Arithmetic average (mean); Md = Median (middle); N = Number of respondents. TABLE 15 OTHER-EXPERT RATINGS OF DRIVING SITUATIONS AND OPERATIONAL PRACTICES
41 safety positively or negatively. It added, âFor example, what carrier efficiencies affecting safety (positively or negatively) have we missed?â The following are selected responses: â¢ Management safety attitude; pressure by brokers; drivers not being responsible on their time off and resting. â¢ Managers of well-managed operations pay attention to all aspects of their operations. â¢ The biggest single determinant of overall safety is risk exposure. Interstates, because they are divided traffic- ways with no at-grade intersections are 400% safer than U.S. and state routes. More than 70% of fatal truck crashes occur on these latter roads, not Interstates where all the enforcement attention and focus takes place. Carriers operating mostly on non-Interstate roads are much more at-risk than those that predominantly travel up and down Interstates. â¢ Driver monitoring with feedback on lane deviations and hard-braking events. â¢ Intermixing passenger vehicles and heavy vehicles on two-lane freeways, especially with rolling terrain and significant speed differentials. â¢ Some efficiency measures in dispatch may result in non- rested drivers being given long runs that will result in fatigue. â¢ Some standard practices with respect to vehicle type, operations, and schedules may promote efficiencies but not fit a driverâs ergonomic needs, circadian rhythm, and temperament, which often leads to increased risk. â¢ Driver training programs. â¢ Onboard monitoring of driving behavior so safety man- agers can provide feedback and incentives to increase safety. â¢ Some survey questions are too simplistic in what is a complex set of interdependencies. â¢ Need to adopt a systems-based approach, applying a model or framework such as the Haddon Matrix. â¢ Using automated, tamper-resistant monitoring of HOS compliance would affect safety positively and also max- imize efficiency. TABLE 17 OTHER-EXPERT RESPONDENT EXPERIENCE AREAS â¢ To manage efficiency implies an organizational struc- ture that can also manage risk. Information About Respondents The years of motor carrier safety experience of the 32 other- expert respondents, addressed by Question 21, ranged widely from 5 years to 40 years. The mean was 19.3 years. These respondents were also asked in Question 22 to indicate their professional experience areas relating to motor carrier safety. The breakdown is shown in Table 17. The percentages shown sum to well over 100%, because most respondents gave mul- tiple responses. The results show that the experience base of the other experts was both extensive and varied, with heavy representation of individuals with backgrounds in govern- ment, industry trade associations, safety consulting, accident investigation and data analysis, and motor carrier safety research. (29) What is the relationship between carrier efficiency and safety? Circle the letter of the statement you most agree with. N (a) Highly efficient carriers tend also to be more safe than other carriers. 26 (b) Carrier efficiency and carrier safety are largely unrelated to each other. 2 (c) Highly efficient carriers tend to be less safe than other carriers. 0 (d) Donât know/no general opinion. 3 Total: 31 No.:aerAecneirepxE 7tnemecrofnetnemnrevoG)a( (b) Other government (e.g., rulemaking, policy) 15 8noitaicossaedartyrtsudnI)c( 5revirdlaicremmoC)d( (e) Carrier safety director/manager 3 (f) Other carrier management position 3 (g) Safety consultant or vendor to fleets 7 (h) Accident investigation/data analysis 15 71hcraeserytefasreirracrotoM)i( 0tsilanruoJ)j( (k) Driver trainer/training development 4 2sreirracrotomrofecnarusnI)l( 3rehtO)m( Average Number of Experience Areas/Respondent 2.8 TABLE 16 GENERAL RELATIONSHIP BETWEEN CARRIER EFFICIENCY AND SAFETY FOR OTHER EXPERTS