The National Highway Traffic Safety Administration has produced a minutely detailed document addressing and attempting to assess driver distractions. According to its numbers, "17 percent (an estimated 899,000) of all police-reported crashes reportedly involved some type of driver distraction in 2010." Out of that number, three percent, or 26,000 accidents, were caused by distraction from "a device/control integral to the vehicle," such as a navigation or infotainment system.
The document provides voluminous guidance to reduce or eliminate possibilities for distracting the driver, and at first glance, their adoption would seem to make in-car navigation systems useless. One of the guidelines suggests that "Systems providing non-safety-related dynamic (i.e. moving spatially) visual information should be capable of a means by which that information is not provided to the driver." Another states that "static or quasi-static maps" are fine – a quasi-static map being one that's updated every few seconds, but "Dynamic, continuously-moving maps are not recommended."
These are only guidelines and they're full of loose phrasing, but the question is what kind of visually useful navigation system could be built to satisfy them. They appear to allow for audio-only navigation while driving, but making maps either inaccessible to the driver or only refreshing them every few seconds would make such systems useless unless a driver can get by with knowing his position once every four seconds. Again, this is only a document that attempts to pair suggestions to evidence derived from hard data, but as far as a practical solution to driver distraction, this might not be the road map drivers or automakers are looking for.