Developers of navigation apps and hardware must place great care in creating an experience that doesn't unnecessarily distract the driver. For example, quite a few involve "lane assist" features that starkly indicate the options when coming to a fork in the road so that the driver avoids having to stare at the screen too long to figure out the right path. In addition, spoken instructions have long been a defining commodity. While Telenav, for example, offers a free version of its navigation app, it doesn't include such audio. And Nokia recently followed suit with its distribution strategy around Nokia Drive, leaving the version with spoken turn-by-turn directions exclusive to its Windows Phones.