Is it possible for my car to inform me of the speed limit?

It's easy to be influenced by the flow of traffic on an open highway. There's a sense of safety in numbers and comfort in following the crowd. Drive too slowly and you might face the honking disapproval of others. Go too fast and you risk drawing the attention of speed cameras and police officers with radar guns. The best way to avoid those flashing blue lights and costly fines is to follow the speed limit, but what happens when you're unsure of what it is?

It can happen to anyone: you hop onto an interstate ramp or navigate winding rural roads, only to realize you’re not sure whether the speed limit is still 65 mph (105 kph) or if you missed a sign. In many places, you can rely on the default speed limit. For example, in California, the default highway speed limit is 65 mph, so if you're ever in doubt, it’s a good benchmark. But knowing the speed limit isn’t always enough. You could still get a speeding ticket if you’re driving too fast for the weather conditions, like fog, even if you're within the posted speed limit.

Sometimes it feels like law enforcement doesn’t want you to know the speed limits. This leads to the all-important question: can’t my car simply tell me the current speed limit? In today’s world, where GPS devices have largely replaced paper maps, wouldn’t it be reasonable to expect a built-in speed limit indicator in vehicles? Such a feature would not only make the roads safer but also ease driver stress.

Keep reading to learn more.

The Road Ahead: Speed Limiters and Smart Speed Adjustment

While the 21st century hasn’t fulfilled all the futuristic dreams once imagined, it has made our driving experience feel more like something out of Knight Rider. GPS technology now tracks our exact location, cars can park themselves, and with the right gear, you can check your dashboard to know exactly what the speed limit is. Unfortunately, flamethrowers and ejection seats still aren’t standard in most cars.

With a GPS receiver and a relatively clear sky, drivers can pinpoint their exact location on the planet. This works because the GPS device communicates with at least four of the 24 orbiting satellites [source: Global Positioning System]. The device uses the signals from these satellites to calculate its distance and determine where it is on Earth. Pair this with a digital map, and there's no need to struggle with heavy and confusing road atlases anymore. Most map providers keep their data updated with current road names, cities, and locations, though it's always a good idea to download the latest updates frequently.

Some GPS apps allow users to set custom speed alerts. However, these devices are quickly becoming outdated as many GPS gadgets now go above and beyond by actually displaying the speed limit for a particular road. Often, this information is shown alongside your current speed, since GPS can track that as well. Still, the technology isn't flawless. While such systems tend to work well on highways, they might struggle with less-traveled rural routes.

For those who like to push their speed limits, this technology might feel unsettling. As it evolves and becomes standard, the cars of the future will inevitably know exactly how fast they should be going at any given moment. How long until lawmakers connect the dots and create cars that cannot be driven over the speed limit? Perhaps sooner than expected.

In Japan, the new Nissan GT-R already features a speed limiter or intelligent speed adaptation (ISA) system. Unless the car is driven onto racetrack GPS coordinates, the onboard computer will prevent the vehicle from exceeding 112 mph (180 kph). This feature keeps drivers from reaching dangerous speeds, capping them at potentially life-threatening levels, but what happens when ISA systems become even stricter? In the UK, lawmakers and safety advocates continue to push for mandatory ISA systems in cars, arguing that it would reduce accidents, traffic, and pollution. In 2003 and 2004, researchers at Leeds University tested 20 ISA-equipped vehicles with mostly positive results. However, critics claim ISAs would create more issues by turning drivers into unthinking robots.

Could such advancements eventually lead to highways filled with self-driving cars? Many futurists and transportation experts believe so. For now, though, no machine overlords are going to force Sammy Hagar to drive 55. But if he chooses, he can always buy a GPS gadget to tell him when it’s time to slow down.