Table 3.

Mean values for each drive and measure of risk (unadjusted).

	Measure	Excluded + passive passenger			Excluded + risk-accepting passenger			Included (fair play) + risk-accepting passenger
		N	Mean	SD	N	Mean	SD	N	Mean	SD
Study 1: males (N = 112)	Failure to stop – baseline solo (%)	40	59.25	40.91	36	48.61	36.27	36	55.00	37.83
	Failure to stop – experiment/passenger (%)	40	50.00	43.85	36	46.39	39.51	36	58.06	37.33
	Percent time in red – baseline solo (%)	40	36.30	25.67	36	28.92	22.22	36	32.73	24.18
	Percent time in red – experiment/passenger (%)	40	28.75	26.25	36	25.49	22.59	36	32.63	22.58
	Passed slow vehicle – baseline solo (%)	40	30.00	46.41	35	34.29	48.16	35	34.29	48.16
	Passed slow vehicle – experiment/passenger (%)	40	27.50	45.22	36	52.78	50.63	36	52.78	50.63
	Difference failed to stop	40	–9.25	19.13	36	–2.22	20.02	36	3.06	16.87
	Difference percent time in red	40	–7.56	12.63	36	–3.44	11.77	36	–0.10	11.21
	Difference pass slow vehicle	40	–0.03	0.36	35	0.17	0.45	35	0.17	0.51
Study 2: females (N = 115)	Failure to stop – baseline solo (%)	39	46.41	37.10	39	47.69	35.05	37	55.94	31.57
	Failure to stop – experiment/passenger (%)	39	38.97	34.24	39	44.87	35.16	37	59.46	33.50
	Percent time in red – baseline solo (%)	39	27.48	22.73	39	29.25	22.16	37	33.61	20.83
	Percent time in red – experiment/passenger (%)	39	21.14	19.78	39	25.39	20.42	37	34.11	20.43
	Passed slow vehicle – baseline solo (%)	39	2.56	16.01	39	10.26	30.74	37	10.81	31.48
	Passed slow vehicle – experiment/passenger (%)	39	2.56	16.01	39	20.51	40.91	37	16.22	37.39
	Difference failed to stop	39	–7.44	24.03	39	–2.82	21.14	37	3.51	18.14
	Difference percent time in red	39	–6.34	15.19	39	–3.86	14.04	37	0.54	11.21
	Difference pass slow vehicle	39	0.0	0.0	39	10.26	30.74	37	5.41	32.88