Table 1.

Phase 1 treatment assignments and retention in phase 2

Sticker type		Phase 1 recruitment	Phase 2 retention
Pure control		2,093	82%
Placebo		1,759	77%
Treatment stickers		7,885	73%
Total		11,737	75%
	Individual action		Collective action
Treatment groups	Phase 1 recruitment	Phase 2 retention	Phase 1 recruitment	Phase 2 retention
Text only	971	73%	979	70%
Supportive (voice)	1,000	71%	998	72%
Consequence aversion (injuries)	974	75%	980	76%
Event aversion (crashes)	992	70%	991	72%
Total	3,937	72%	3,948	73%