The Good: On the road, Waze excels in one very critical way: traffic accuracy. It also helps that the app is free and doesn't require you to set up an account before using. The Bad: The user interface is unattractive and can be difficult to use. Voice command is hidden in the menu. The Bottom Line: For anyone looking for more reliable traffic data than Apple's and Google's stock maps applications, Waze is definitely worth a download. , Waze is a community-powered mapping and navigation app that gives you real-time traffic information and road alerts. Because it's free, accurate, and feature-packed, it is rightfully considered one of the top apps in its category. But don't think of Waze as a full-fledged alternative to Google Maps. Since the app is primarily designed for use while driving, you won't find any transit or walking directions built in. Also, you won't get 3D buildings or topographic data like you will with Google Maps or Apple Maps, but as we don't do much driving through buildings, we won't count that against Waze. You can use the app without an account, but setting one up does give you more options to contribute to the Waze community.Maps and traffic What makes Waze such a powerful app is its rich and constantly updating database of information. Its millions of users who are actively and passively contributing countless data points altogether create accurate maps (in our testing grounds of San Francisco, anyway) that would make any cartographer proud. And of course, the app distills all of this into usable traffic data for you to see on screen. Road closures due to extensive construction are accurately represented, and one-way streets and turn restrictions match their real world analogs. If you find anything out of sorts, it's easy enough to mark a map issue with two or three taps.As important as mapping accuracy is, is the accuracy of its traffic and incident data. If Waze says there's a traffic jam on a particular stretch of road, odds are better than good that it's correct.As you drive along, Waze will periodically notify you via pop-ups of incidents on the road ahead within a preset radius or along your chosen route if a destination has been set. Slow traffic, incidents and accidents, and police presence and speed cameras are among the possible triggers for notifications. That Waze will provide these notifications even if you do not have a destination chosen adds incentive to always have the app running when behind the wheel and on the road; of course, you'll also be doing your part to improve the map and traffic data available to the whole Waze community by doing so. Waze will also occasionally display pop-up ads for nearby businesses, but only when the vehicle is stopped, such as when waiting for a red light. We should note that Waze isn't the first navigator to display ads; portable navigation devices have been using this trick for years to subsidize their free traffic data.Navigation Where Waze falls a bit flat is its user interface. The maps are easy enough to read, but the app's Menu and Reporting buttons are tiny and tucked into the lower corners of the screen. Tapping them causes pop-up menus to appear with more options and larger buttons, but that still means that the driver is at least three taps and possibly a swipe away from choosing a preset destination, such as home or work.