Garmin is trimming the size of its newest series of portable navigation devices (PNDs) while bulking them up with features.

Three Nuvi 3700-series models shipping in the third quarter look almost like iPhones, coming in at 0.35 inches in depth. That’s about half the depth of other Nuvi PNDs.

The three models are the $349-suggested 3750, $399 3760T and $449 3790T. All feature 4.3-inch capacitive-touch WVGA display.

Into these devices, Garmin is packing such new features as 3D terrain view in the flagship model, and in all models, it’s incorporating new predictive routing capabilities as well as accelerometers to reorient the display to portrait mode for use by pedestrians.

All models also feature newly enhanced touchscreen-swiping capabilities. Users will be able to swipe the screen to reposition a map as they have with previous Garmin models, but now they can also double-tap or pinch the map to zoom in and out of a map as well as change the display from a birds-eye view to a 3D view, said spokesman Ted Gartner.

The new predictive routing capabilities in all models include MyTrends, which takes a user’s previous driving habits into account when making route calculations. The device will remember whether the user likes to avoid highways, for example, and it will use the speeds at which a driver normally drives on a specific road to calculate an estimated time of arrival. The device will also automatically predict a route that a driver wants to take at specific times of the day. For example, it will calculate a route home at 5:30 p.m. every weekday if the car is parked at work.

Another predictive routing capability, called TrafficTrends, calculates optimum routes by using historical traffic data and recurring trends that Garmin has collected about traffic in a given area at any given time or day.

When placed in a new sleep mode, intended mainly for pedestrian users, the PNDs remember their location so that when they’re turned back on, they don’t have to spend any time acquiring GPS satellite signals before they calculate a new route.

Another new capability automatically reorders multiple waypoints into the most efficient route.

Like other Garmin models, the flagship 3790T and the 3760T feature built-in RDS-TMC FM receiver to receive Garmin Connected services information, including traffic and weather. Both also feature Bluetooth for hands-free calling. The flagship 3790T adds voice control of functions, voice entry of destination, and 3D terrain view, but unlike previous voice-enabled models, drivers no longer have to put it in voice-recognition mode by pressing a button on a steering-wheel-mounted remote. Instead, users need only speak a wake-up phrase that they can customize.

All three feature Garmin’s Eco Route capability, which selects the most fuel-efficient route to a destination, and ability to add map of a European cities at $10 to $15 per city. The maps can be downloaded by PC or purchased preloaded on an SD card from Garmin.

The three also feature a previously available enhanced pedestrian mode, enabling users to download optional CityXplorer public-transit information on a city-by-city basis. With it, users can select a combination of buses, tramway, and metro and suburban rail systems to get about.