The "one risk" campaign has been developed by M&C Saatchi with a film that tests viewers’ decision-making with a selection of conundrums.
It starts with everyday choices such as "tea or coffee", and "staying in or going out" for an evening. The film suddenly moves to decisions on the road such as "wait or go", and "fast or slow".
The viewer is then presented with the consequences of one bad decision on the road with choices including "stitches or crutches", "brain damage or paralysis", and "nightmares or guilt".
Miranda Leedham, the head of marketing operations at TfL, said: "Much like drink driving is now sociably unacceptable, careless and dangerous road behaviours need to be considered in the same way.
"It only needs one person taking one risk to affect so many lives, and if this campaign ensures a single road user thinks twice, it will be worth it."
The ad was created by Curtis Brittles who handled the copywriting, and Will Bates took charge of art direction. MEC is the media agency for the campaign.
Luke Boggins, a creative director at M&C Saatchi, said: "The opportunity to change road user behaviour with creative work is one we relish working with TfL.
"The simplicity of the ‘one risk’ campaign will resonate with everyone who’s told themselves they only behave dangerously on the road the odd time or once."