Staplin and Gish (2005)

1. Staplin and Gish (2005) • Potential impact of driver turnover • Replacement costs, etc. • Greatest impact may be the area of safety (higher crash rate) • Previous studies • Some evidence that carriers with higher driver turnover has higher crash rates. • Reliable estimate of the actual extent to which crash risk is increased as a function of job-change frequency is lacking.

2. Goal of the paper • Quantify risk function • Test the statistical significance of the relationship between job change rate and crash rate • Focus on crash data of for-hire interstate drivers.

3. Method • Analyze data from inspection records maintained by Federal Motor Carrier Safety Administration (FMCSA) • Fatal, injury, and/or two-away crashes • Job change rate is measured by the number of different carriers a driver has worked for in a given time interval. • Use odds ratio to measure the relationship strength. • Use two types of crash indicator: (1) one or more crashes, and (2) two or more crashes. • The latter is more likely to reflect driver’s fault.

4. Data • Data errors removed • Time interval should not be too short or too long (2 years or longer) • Final data included 25,609 drivers, of which 16,249 had no crashes, 8,797 had one, and 563 had two or more crashes. • On average, drivers in sample had 6.1 inspections (ranges between 2 and 20).

5. Results • One job change = more crash-free drivers • Two or more job changes = more crash-involved drivers. • Odds of crash increases by 60% for drivers with 6 or more job changes (no crash vs. one or more crashes). • Odds of crash increases by 120% for drivers with 6 or more job changes (no crash vs. multiple crashes).

6. Results (cont.) • Odds ratio increases sharply when a driver change jobs more than 2.5 times per year. • Even more dramatic increase for drivers with 3 or more job changes per year.

7. Discussion • Proportion of crash-free drivers decline, without exception, as the job change rate increases. • This relationship was most evident when the analyses focused on multiple crash data. • If a driver changes jobs more than twice per year, the odds of crash begin to increase • If changes job more than three times per year, crash odds is more than twice as high as those drivers with fewer job change rates.

8. Questions • Given this study result, what should you, as a carrier manager, should do. • How do you balance the safety and driver turnover issues? • What are the lessens from this study for shippers? • What are the lessens from this study for policy makers? • Does this study result give you some implication on how you play simulation game?

9. Mejza et al. (2003) • Prior studies of truck safety • Effect of carrier behavior on safety performance • E.g. effect of noncompliance with HOS regulation on safety performance • Present study • Investigation of the characteristics of “best safety performers”. • ID best performers • Learn safety management used by best performers

10. Focus • Driver selectivity • Instructional intensity • Supportive and motivational intensity • Sample • Use SafeStat of FMCSA to list best 20 safety performers in each commodity category • Surveyed 192 carriers • 141 usable sample data • Results

11. Management Implications • Be selective • Training (multiple) • Use multiple rewards

12. Discussion questions: • If you are the carrier having poor safety record, what would you do? • Do you rather hire drivers that have safe records or do you rather hire drivers that are likely to stay longer? • Quality drivers may demand higher salary than others. Do you still want to hire them? • If drivers are not driving safely, what impact does it have on carriers? • What role does safety play for establishing relationships with shippers and consignees? • Why is it important to survey the non-safe carriers too? • What other factors would you consider as determinants of safety?