Conceptualizing and measuring confidence in older drivers: development of the day and night driving comfort scales.

OBJECTIVE

To examine and measure driving confidence from the perspective of older adults.

DESIGN

Used focus groups for construct examination, item generation, and ratings; conducted psychometric testing using Rasch analysis for scale refinement; examined test-retest reliability and associations with driver characteristics and driving habits.

SETTING

Retirement complexes and seniors' housing and centers in Ontario, Canada.

PARTICIPANTS

Convenience samples of current drivers (n=143) (range, 66-92y) and 7 counselors.

INTERVENTIONS: Not applicable.

MAIN OUTCOME MEASURE: The Day (DCS-D) and Night (DCS-N) Driving Comfort Scales developed inductively with older drivers.

RESULTS

Older drivers believed that it was important to consider confidence in their own abilities and discomfort caused by other drivers, to separate day and night driving, and to specify the driving context (eg, traffic flow, speed). Rasch analysis showed that the final 13-item DCS-D and 16-item DCS-N were both hierarchic and unidimensional, with good person (.89, .96) and item (.98, .97) reliabilities, respectively. Test-retest reliability was adequate for the DCS-D (intraclass correlation coefficient [ICC]=.7) and good for the DCS-N (ICC=.88). Scores were significantly associated with reported driving frequency, situational avoidance, and perceived abilities (P<.001).

CONCLUSIONS

The Driving Comfort Scales are promising new tools for research and practice.