Typical advantages of these are that they are often free, involve hardware (a phone) that you already own, and are always up-to-date.

How they work: Hop in the car with your smartphone and choose a pre-loaded app such as Google Maps or Apple Maps (or download the likes of Here, Waze, or Mapquest) and your phone service gives you multiple options for a smoother trip, complete with traffic views, alternate-route suggestions, and warnings if you’re going too fast. The often-bright displays of these apps can make them easy to read on a sun-drenched dashboard. Plus, you don’t have to buy any other GPS device—because you already have the smartphone—nor do you have to worry about carrying around a portable navigation device (PND).

Phones can also do things PNDs can't, such as warn you to leave early for a calendar appointment if traffic looks bad. Or, based on your past history, a phone app shows estimated travel time to your frequent destination on the lock screen. If you don't particularly like the navigation app that came with your phone, you have other great choices via the app store, many of them free (see “Free Ride: Top Map Apps” below for more info). Compared to portables or most in-dash options, the apps are easier to update, automatically loading the latest maps.

Consider this: Using phone-based phone GPS apps eats up precious data from your monthly plan, and some conk out during phone calls or when your cellular signal drops. (Some apps work around this by saving maps to your phone, so you won't lose your way—even if you lose phone service.) Whichever option you choose, you’ll likely need to purchase a mount, car charger (since navigation can quickly deplete a battery), and possibly a data plan for your phone (if you don’t already have one).

Carmakers' built-in proprietary infotainment systems typically work without a plugged-in smartphone.

How they work: It used to be that integrated factory systems were often the most expensive type of navigation aid. However, more and more cars are rolling off the assembly line complete with multifaceted infotainment systems that combine hardware and software to do things like regulate climate controls, provide updates on the engine and other systems, offer Bluetooth connectivity, in-car internet, wifi, and, typically, offer a navigation option.

Newer cars have the infotainment system screen built into the dashboard, and you adjust it using the touchscreen, steering wheel controls, or voice commands. With older cars that aren’t infotainment system-capable, you could install a GPS unit but would still need a professionally installed aftermarket head unit to run a full infotainment system. Like PNDs, built-in GPS systems work via satellite, so you won’t end up lost if you lose cell phone service.

Consider this: In our tests, we find that the quality of the carmakers’ branded infotainment systems varies widely and high-rated systems don’t necessarily align with high-rated cars. If you don't like the infotainment system that came with your car, you can opt for phone-based apps such as Google's Android Auto and Apple CarPlay, which plug your smartphone into a car that supports either app.

See our reviews of infotainment systems proprietary to brands as well as the favorites from our survey covering more than 58,000 cars.

These integrated infotainment systems are built into your car, or professionally installed aftermarket, and use either a plugged-in Android smartphone or iPhone as a conduit.

How they work: Increasingly, new cars come equipped with infotainment systems, a mix of hardware and software that combines information and entertainment to give access to navigation and audio systems, USB and Bluetooth connectivity, in-car internet, and wifi, among other features. There are proprietary infotainment systems from carmakers such as Chrysler, GM, and Hyundai that run without a phone (see “In-Car Infotainment Systems…” for more on these), but more and more automakers are supporting these two smartphone-based infotainment systems from Google and Apple. Android Auto and Apple CarPlay plug into a system-supporting car and, voila, you’re seamlessly connected. A modified version of your smartphone screen (with larger icons and an edited-down menu) appears on the in-dash screen, allowing you to use the phone and apps in a less distracting way. Since you’re already addicted to…er, familiar with your smartphone’s ways, this saves the bother of learning the ins and outs of an automaker’s (possibly clunky) proprietary system. Older cars would need a professionally-installed aftermarket head unit. The current market price for Caplay/Android Auto-capable units is around $500 (installed).

Consider this: Since it’s your phone, you already know how it works, and can “Hey, Siri” and “Ok Google” as usual. However, these platforms only run approved apps—for example, you can’t get Google Maps on Apple's system, and you might want to check that your favorite music-streaming service or podcatcher is supported. The phone-powered navigation automatically updates maps and other apps.

These “concierge”-style call buttons came on the scene in the mid 1990s.

How they work: Carmakers combine GPS and cellular technology to access emergency help or a variety of convenience services from the vehicle. Systems include BMW Assist, GM OnStar, Toyota Entune, Hyundai Blue Link, Lexus Safety Connect, and Mercedes-Benz mbrace. Specific services—both paid and free—vary. The systems typically offer a menu of services, including emergency crash notification and assistance, a stolen-vehicle locater, and roadside assistance. Some telematics systems will unlock your car door remotely.

Navigation is typically one of the services provided, via a basic graphic display showing each coming turn along with voice direction. Advantages include ease of use and being able to ask for directions by talking to a human at the other end of the line, even while driving. Another plus is that you don't have to pay for updated mapping information. Older cars with telematics but lacking dash screens will have you interact with a computerized voice when getting directions.

Consider this: On the downside, these systems can be expensive and you have to be in an area with good cell phone coverage for them to work. Typically, The vehicle has to be equipped from the factory, although some companies offer costly aftermarket installation. Car companies may offer an initial trial period of the service, then charge a service fee. It’s a good idea to study up beforehand on what is a paid service and what’s not. Check with individual carmakers for more info about particular systems.

The name says it all—they can move with you from car to car.

How they work: Like built-in systems, these are connected to a satellite, so—unlike cell phone apps—they can never freeze and leave you stranded when you lose phone service. Portables usually offer the same features as built-in systems, plus more—and often cost less. Typically, the volume can be turned up louder than phone apps. Portables are compact and easy to carry with you or share with others. Real-time traffic reporting is usually reasonably priced and voice commands are sometimes available. We’ve found that map updates are less costly (than with built-ins); some models even come with lifetime updates for a modest charge. Some newer models come with Bluetooth hands-free calling and dashboard camcorders that can save footage of a trip, and, in the case of an accident, capture still images.

Consider this: Screens are usually smaller than in-dash models, and potentially hard to read. Voice command programming capability is so-so, compared to the best car systems. These should be securely mounted and placed where they won’t interfere with airbag deployment or block visibility. Other disadvantage: Your phone already has built-in GPS with a free app. Buying a portable device is an additional purchase—and something to carry around.

It’s worth noting that battery life is minimal or can decrease over time. If the battery loses its charge, you have to connect via power cord. It’s best to routinely charge the battery; when batteries die on some models, the unit must be replaced. And, usually, when you leave the car, a portable should be hidden or removed to deter thieves. Prices range from about $80 to $400.