The present study aimed at identifying factors for traffic safety support in older drivers. This was achieved by studying the co-operation between older drivers and their ordinary front seat passenger (co-driver). The knowledge emerging from such study can enhance the understanding of what kind of support an older driver needs and also help facilitate proper design of in-vehicle support systems and intervention training programs for older drivers. A within group field study was carried out, using a mixed-methods evaluation design. Four elderly couples participated in the study. The drivers included in the study requested and received on-going directional support, traffic -and driving strategic help, help with look-out and reminding of current speed limit. It was evident from comparisons between interview data and field data that how the participants themselves described their need of support differed from what support they requested (drivers) and gave (co-drivers) in real driving. Furthermore, data revealed that three out of four drivers were given a score of 2 in the Useful Field Of View test (UFOV). It was evident that there are areas in which older drivers need and request support. The results from the present study could be used in the design process, and in evaluation of, in-vehicle support systems as well as in developing intervention training programs customised for older drivers.