Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
Intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text on the opening pages of each chapter.
Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.
Do not use for reproduction, copying, pasting, or reading; exclusively for search engines.
OCR for page 38
38
TABLE 11
SUMMARY STATISTICS ON PROFESSIONAL EXPERIENCE OF
SAFETY-MANAGER RESPONDENTS
Statistic
Range Median Mean StDev
Question
(32) Number of years experience as carrier Safety
2 to 45 10 13.2 9.1
Manager or Human Resource Manager
(33) Total years experience in commercial truck/bus
5 to 62 22 24.0 12.6
operations
Note: StDev = standard deviation.
their fleets. Table 12 provides summary statistics of their included opinion items, but no items on their operational
answers. practices, because they are not so involved. The data from this
other-expert survey were of interest, although, as it (1) gauges
There are no definitive population statistics to compare expert opinion on questions, (2) points toward areas perhaps
with the previously cited respondent individual and fleet sta- deserving more consideration, and (3) is a way of identifying
tistics. Nevertheless, it is clear that survey respondents gener- ongoing research relating to project topics.
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 Questionnaire Design and Content
trend of larger fleets being overrepresented at virtually all
national and regional safety conferences, and as active mem- The other-expert survey questionnaire was similar to that
bers of national and state truck and bus transport organizations. for safety managers. It consisted of the following general
sections:
Question 35 asked respondents to select the truck or bus
operation type that best characterized their fleet. The num- · A brief statement of the study and survey purpose, with
bers of responses in each category are listed in Table 13. a confidentiality assurance;
Although the question asked for "the" best characterization, · Two related five-choice questions on general factors
many bus safety managers selected two choices ("g" and "h" affecting safety and crash risk (used on paper form only);
in Table 13). Therefore, that dual selection is listed later as a · 16 driving situations or operational practices, each rated
separate choice. on a -3-to-+3 Likert scale (-3, -2, -1, 0, +1, +2, +3) for
effect on fleet safety;
· A multiple choice question on the general relationship
OTHER-EXPERT SURVEY METHODS between carrier efficiency and safety;
· An open "comments" space; and
The secondary project survey was of other experts in motor · Two questions on respondent's years of motor carrier
carrier safety. These individuals were primarily professional safety-related experience and on specific types of posi-
associates of the principal project investigators. They were tions held.
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- Questionnaire Distribution and Analysis
sulting), and research. Many of these individuals are actively
involved in other TRB truck and bus safety activities. Even The other-expert survey was administered only online through
though these individuals are highly knowledgeable, they are TRB's online survey service. The survey solicitation was sent
regarded as secondary respondents because they are (by defi- by means of e-mail to 134 individuals, with a second e-mail
nition) not currently carrier practitioners. Their survey forms reminder sent several weeks later. A total of 32 online surveys
TABLE 12
SUMMARY STATISTICS ON SAFETY-MANAGER RESPONDENT FLEET SIZE
Statistic
Question Range Median Mean SD
(34) Approximate number of power units currently 14 to 15,000 112.5 866 2,201
in fleet
