What's missing from the heroin analogy is fact that the dangers faced by cyclists can be changed - if drivers see a cyclist every 5 minutes vs every 1 hour, they'll be looking out for bicyclists constantly.
Take it to the logical extreme, imagining legalization of heroin and subsequent widespread use and sale in convenience stores, and it'd be way safer, because you'd always be getting a standardized product.
That definitely was true for a while, not sure about in the last few years. A less controversial analogy might be with coffee, where the rate of people overdosing is probably lower now that it's no longer mainly used by Sufi mystics in enormous doses for entheogenic purposes.