In today's era of self-driving vehicles, navigation systems have become ubiquitous, greatly facilitating driving across the United States. However, relying solely on electronic devices can be precarious, as GPS technology is not infallible.

Thus, it remains imperative for drivers to possess a fundamental understanding of the highway system and associated signage in the United States. This comprehension serves as a crucial backup, ensuring safe and efficient navigation even in instances where technology may falter.

When it comes to speed limits, it's important to understand that they represent the maximum allowable speed for driving. However, there's a general belief that exceeding or falling below the limit by up to 5 mph typically doesn't lead to police intervention. Yet, if one exceeds the speed limit by more than 15 mph, especially on highways where the limit is 55 mph or higher, it can result in immediate revocation of the driver's license.

Some individuals may choose to drive slowly for safety reasons. However, it's crucial to note that driving excessively slowly can also pose risks. Officials warn that driving at very slow speeds can endanger both the driver and others on the road. For instance, driving too slowly on high-speed roads can increase the risk of rear-end collisions due to insufficient braking time for other vehicles. If opting to drive at a reduced speed within legal limits, it's advisable to use the rightmost lane and allow faster-moving traffic to pass safely.

The highways in the United States comprise four distinct systems: interstate highways, national highways, state highways, and county highways. Interstate highways, primarily expressways with a minimum of four lanes, are federally funded and managed. Their emblem features a shield with a blue background, and the road number is displayed in white. Speed limits on interstate highways vary by region, generally ranging from 55 mph near major cities to 65-80 mph in suburban areas.

The U.S. Highway System, also known as "Numbered Highways in the United States," is an extensive road network combining both ordinary roads and expressways. Initially the primary highway system before the completion of the interstate highways, mainly consisted of two-way, two-lane roads. Over time, as interstate highways were completed, the utilization of national highways decreased, with some even becoming obsolete.

Intrastate expressways, situated within states, typically include a mix of major and minor arterials. The quality and standards of these roads vary, with higher-traffic routes often meeting interstate highway standards.

County roads, maintained by individual counties, represent the lowest administrative-level expressways. Ranging from frequently used multi-lane highways to remote dirt roads, not all states have county roads, and signage may be absent in areas where they exist.

While highways in the United States are generally toll-free, there are exceptions in the form of toll roads. These roads feature cameras that capture images of passing vehicles' license plates. Subsequently, bills are sent to the registered owners' addresses, even if the vehicle is not registered in the state where the toll road is located.