Useful Notes / American Driving Laws

Rule Number 1: The bigger, uglier car always has right of way.

Rule Number 2: Never, ever, make eye contact.

Car Talk

Some basics:

• Americans drive on the right-hand side of the road. One-way streets are, of course, an exception.
• American Federalism means that State Governments are responsible for driving laws and roads within their borders. Even the 'Interstate' highways are built and maintained by the various state governments, albeit with significant federal financial support. Most State governments also maintain state highway systems while local roads and streets are typically a local government responsibility. Though, it's important to note that the national government ("federal government" in American parlance) can and does encourage certain policies (speed limits, driving age, truck cargo/commercial restrictions, etc) using the power of the purse. Since refusal to adhere to Federal standards regarding roads means the withdrawal of Federal tax revenue for upkeep, states will fall in line before they'll even consider assuming 100% of the maintenance costs. There is no Federal agency for street-level enforcement; traffic regulation is entirely a state responsibility with local enforcement delegated to local governments. You'll never see the FBI pull someone over for speeding on the interstate.
• With that said, traffic laws are largely uniform with minimal variations around the edges — like verbiage on informational signs and ancillary rules like when one can make a right turn on a red light. Standardized rules for lights, signs and signals are published in the Manual of Uniform Traffic Control devices, or MUCTD. Individual jurisdictions can and will opt out of specific MUCTD rules but typically don't contradict them. For instance, sign shapes and colors are standardized nationwide. If you've ever wondered why some signs have distinctive shapes while others do not, the signs with distinctive shapes are all signs (Stop, Yield, Passing Zone, etc,) that must be recognizable from the back. Canada also follows these same uniform laws, so most of what you see on this page (with the exception of the part about different license types) also applies there.
  • One case where state laws can differ is laws regarding stopping for a school bus. All U.S. jurisdictions require traffic going in the same direction as a school bus, plus opposing traffic on a two-lane road, to stop for a school bus that's picking up or dropping off children. (The bus will display flashing red lights and a stop sign when this happens.) The differences arise for opposing traffic on roads with more than two lanes, with a few examples for illustration.
    • New York state and West Virginia require all traffic to stop. Period. (The only exception is on controlled-access highways, where traffic is never intended to stop.)
    • In Indiana, opposing traffic has to stop unless the road has a physical barrier (including a grassy median).
    • In California, Idaho and Kentucky, opposing traffic does not have to stop, even if the only divider is a double yellow line.
    • In Washington state only, opposing traffic does not have to stop on any road with more than two lanes. This includes two-lane roads with a center turn lane.
• There are three lights on a traffic signal, which describe how you're supposed to act. Typically the traffic signal itself is vertical, top to bottom, but occasionally they are side-to-side, at which point the right side counts as the "bottom".
  • Bottom is green, which means you can proceed.
  • Center is yellow or amber, and means, "If you are approaching the intersection but have not crossed the line into the intersection, you need to stop." In practice, aggressive drivers take this as, "Speed up, let's see if we can get through!"
    • The existence of this light at all has to do with the "Too Fast to Stop" trope. If you are close enough to the intersection that you should stop, but have enough speed that you can't without ending up coming to a complete stop in the intersection / smack-dab in the way of oncoming traffic, you have crossed the "Point Of No Return." Under these circumstances it is permissible to keep going, speed up or even run the red light—it's an unsafe action, but trying to stop (and failing) would be even more so. However, this is never an excuse to exceed the speed limit.
  • Top is Red, which means, "Stop and remain stopped until the light turns green." The sole exception is certain turns, explained in the next bullet point. If there is a green arrow light, you can turn on a red light in that direction without stopping. Or there can be a red arrow when you're at a green light, which means that even though you have a green light you can't turn that way until you get a green arrow.
• You can make a right turn at a red light provided you stop and verify that you have the right of way first. In most states this is from the far right lane only. This is because Americans drive on the right—you don't have to thread through crosswise traffic to do this, you just go from a far-right lane to a far-right lane. However, some intersections may have a "No Turn on Red" sign posted if "right on red" cannot be made safely. A red arrow light means the same except in Kentucky, where only the "No Turn on Red" sign prevents a right on red. These signs and lights are often ignored or legitimately overlooked. Note that in New York City, right turns on red are prohibited unless the intersection is specifically posted as allowing such turns.
  • Left turns are very different from right turns since you have to make them through crosswise traffic. There are two basic kinds of left turns: "Protected" and "Unprotected". A protected left has a traffic light controlling it—a green arrow pointing left, and the traffic signals programmed to stop traffic coming in the other direction. Unprotected lefts have no such: you just have to lurk in the left lane waiting for a gap in oncoming traffic. Depending on what that traffic is like when you attempt this, it can take a while. And god forbid you be on a one-lane road, so that the "left" lane is the only lane and everyone is piled up behind you honking their horns. Semi-protected lefts show a green arrow when the left turn is protected and a flashing yellow arrow when it is unprotected. Some people find this confusing. Some states (but not all) allow a left turn on red from one one-way street to another. Again, because you are not crossing traffic.
    • If you find yourself in a city with a lot of unprotected or no left turn lanes, it would be best to do three right turns. This is particularly a problem in places like San Francisco to the point where couriers and other delivery services modified their routes for right turns only to increase fuel efficiency. ^note  This trope was even tested by MythBusters (who themselves are based out of San Francisco), who confirmed that a route made entirely of right turns does lead to improved fuel efficiency for a delivery truck.
  • Left turns on a red light are allowable in two extremely specific circumstances:
    • First, if the car attempting the turn was already in the intersection before the light turned red, it is allowed to complete the turn in order to clear the road (see above for the rules on running a yellow/red light, for exactly the same reason). Drivers attempting to make an unprotected left thus tend to stop their car in the intersection when waiting to turn. This gives traffic behind them room to pass on the right, and guarantees that they'll get to make their turn, since in the worst case the light will turn red and they'll be "forced" to turn to clear the intersection.
    • Obviously if you are in the way of an emergency service vehicle, you're legally obligated to get out of the way. If you must get into an intersection, do so carefully.
    • In 37 states and Puerto Rico, you can turn left on red if both the origin street (the one you're on) and destination street (the one you're turning to) are one-way. In Alaska, Idaho, Michigan, Oregon, and Washington state, only the origin street has to be one-way, and in Washington state (but nowhere else), freeway off-ramps are treated as one-way streets for purposes of this law. Left turns on red are banned in eight states and two territories.^note Totally banned in Connecticut, Maine, Missouri,, New Hampshire, New Jersey, North Carolina, Rhode Island, Washington, D.C., and Guam; banned in South Dakota unless allowed by local ordinance. New York City has the same policy for left on red as it does for right on red—banned unless intersection signage specifically allows it.
• Speed and distance are more often than not (and by this we mean almost always^note There is one major exception: Interstate 19 in Arizona, which measures distance in kilometers. This was done as part of a failed attempt to convert the US over from US Customary units to SI units) measured using American Customary Measurements; you may, for example, be told that you are 106 miles from Chicago, on a stretch of highway allowing travel at 55 miles per hour. Although it may vary by region, the rule goes that if there is no speed limit sign (and there rarely isn't) then the speed limit is the automatic default of 35 miles per hour (56 kilometers per hour) on local roads and 55 miles per hour (about 88 kilometers per hour) on highways.
• The United States is a big country, with a lot of nothing (many individual states are larger than entire countries ^note Example: Colorado is larger than the entire United Kingdom; while France is barely 3/4 the size of Texas), and not a lot of reason for some of these communities to keep their streets compact. Street networks can be relatively well developed, but most Americans aren't surprised at commutes of 30 minutes. Or more. Indeed, in some metropolitan areas, daily commutes of over an hour are common. In dense urban areas traffic congestion can cause the same problems over a relatively short area. For example, San Francisco is only 7 miles across in either direction, but it is not uncommon to take close to an hour to cross it due to traffic. New York City is the only major city in the U.S. where people that don't own a car outnumber people that do (mainly because most people living there have no place to put a car), to quote Phillip J. Fry: "Nobody drives in New York, there's too much traffic."
• Automobile ownership is extremely common in the USA - prior to the 2008 economic collapse, there were more cars owned in America than there were licensed drivers - and virtually everyone who can drive does so (with the exception of inhabitants of large, dense cities with subway systems, such as New York City or San Francisco... but notably not Los Angeles). While not everyone owns an automobile, practically everybody is licensed to drive one — it's a major rite of passage, especially in rural and suburban areas. As a result, U.S. licensing requirements and driving laws tend to be very straightforward, sensible and practical with little or no quirks or hidden "gotchas" for the unwary.
• While licensing is done at the state level, full faith and credit means that states are more or less bound to honor each others licenses, so someone licensed to drive in New York can rent a car in California and then drive it to any of the neighboring states without having to do anything else. That said, the driver is considered responsible for knowing and obeying the specific laws regarding operation of a motor vehicle of the state he or she is driving in at any given time. More than a few people have found that out the hard way by driving from a state where handguns are allowed to be carried in a car into one where doing so is prohibited. It's not uncommon for there to be supplementary signage posted at state borders reminding incoming drivers of these differences, such as mandatory seat belt usage, different speed limits, or requiring the use of headlights during inclement weather.
• Licenses are standardized as a result of federal law into four classes.
  • Class C is the standard 'passenger' license, you can drive anything under 26,001 pounds. You cannot carry passengers for hire. You also can't drive a motorcycle without a separate endorsement.
  • Class B is the standard for bus drivers and taxicab operators.^note Some states separate this into two different classes, for instance in New York to drive a taxi you only need to pay an extra fee and get a Class E license, but to drive a bus you'd need a Class B Commercial Driver's License (or CDL) with a passenger endorsement, which is considerably more expensive and requires additional testing Allows driving anything weighing over 26,000 pounds and tow anything under 10,001 pounds, and can carry passengers for hire. Same rule as Class C for motorcycles.
  • Class A is a commercial truck driver's license. You can drive just about anything, including vehicles weighing more than 26,000 pounds and towing over 10,000. But you still can't drive a motorcycle. (As noted below, you can also have additional qualifications, such as ability to carry hazardous materials.)
  • Motorcycle endorsement is added if you have a license in one of the other classes, otherwise you have a motorcycle license. So it is possible to only be licensed to drive motorcycles and not allowed to drive a car.
• Because of the requirement that you can only be sued where you live or would normally expect to be "hauled into court" it used to be that if you were rear-ended or otherwise involved in an accident by someone who lived in another state, you had to hire a lawyer in that state in order to sue them. This changed with a special agreement called the "Interstate Driver's Compact" that has been agreed to by Congress, all 50 states, the District of Columbia and all U.S. territories, and all Canadian Provinces. It means that as a condition of being able to drive outside your own state, you appoint the head of the drivers' license bureau for the state where you were driving as your agent for service of process. So the plaintiff can now sue you either in the state where the accident occurred or in your home state.
• License plates, like driver's licenses, are also done at the state level, with each state having its own license plate design and serial number format. The dimensions of the plates are standardized to be 6 by 12 inches. 28 states and the District of Columbia require plates to be displayed both on the front and rear of the car, while 22 states only require rear plates (the most recent state to amend their rule being Alaska, which began requiring only rear plates in August 2022). When a car's registration is renewed, the registration paper usually comes with a sticker (or multiple stickers) that is placed over the previous year on the license plate. New York and Texas require the sticker to be placed on the front windshield rather than the license plate, while New Jersey, Connecticut, and Pennsylvania do not require stickers at all. Most states have other designs available for customers (including plates that bear the names of clubs, organizations, or universities) called specialty plates, and states can also have different license plate designs for specific types of vehicles (i.e. motorcycles, semi trucks, trailers, farm vehicles, and state government vehicles). Additionally, in all 50 states and DC, for an extra fee, it is very easy to get a Vanity License Plate, a plate where the serial number spells out a specific message.
• Interstate numbering is designed to give information about the highway in question:
  • Two-digit interstate are primary roads, meant for long distance travel. (This includes Interstate 5, which runs on the left (west) coast from Mexico to Canada.)
    • Two-digit interstates with odd numbers run primarily north-south, even numbered interstates run east-west. (Note that this is overall, any given stretch of road can go pretty much any direction as dictated by local terrain, and it's not at all uncommon for the same physical piece of highway to be designated as both an odd and even numbered interstate, carrying both signs, where it happens to be convenient^note for example, Interstate 80 is partially interlined with Interstate 35 through Des Moines, Iowa.)
  • Numbers ascend going west to east for odd numbered highways, and south to north for even numbered ones.
  • Two-digit interstates divisible by 5 are major arteries, and usually run the full length/width of the US.
  • Three-digit interstates are auxiliary roads, meant to support the traffic needs of major urban centers. The last two digits come from the primary interstate that acts as parent road.^note There is one exception to this rule: Interstate 238 in California is an auxiliary of Interstate 80. The odd numbering is due to all other possible 3-digit numbers ending in 80 already being taken by other Interstate or State highways and there being no Interstate 38.
    • Spur routes that never return to the originating interstate receive an odd starting number.
    • Branch routes (break off and run parallel before merging) and loop routes (branch to form a ring around the urban center, with the highway running through the ring) receive an even starting number.
• US Highways have a numbering system as well, similar to the Interstate system, with a few differences:
  • While two-digit highways ending in 0 are still major east-west highways, the major north-south highways are two-digit highways ending in 1. There are two deviations from this rule: US 2 is a major east-west highway, and US 101 is considered a two-digit highway, with the first "digit" being 10.
  • Numbers ascend in the opposite direction to Interstate highways (even numbers from north to south, odd numbers from east to west), to prevent US and Interstate highways with the same numbers running through the same state. For the same reason, there is no Interstate 50 or Interstate 60, as they would probably run through the same states as US 50 and US 60.
• Rear turn signals may show red and be combined with the brake lights, which confuses visiting foreigners to no end. Amber rear signals and side repeaters fall into the "allowed but not required" category (as do daytime running lights); side markers have been required since 1968 and with "world cars" becoming more common the presence or absence of an amber side-facing reflector somewhere forward of the front axle centerline is the internet car-spotters surest way of telling whether a car is US- or international-spec (eg. 2012-up Ford Focus).

Speed limits are set by local and state authorities. For a number of years in The '70s and The '80s, the federal government attempted to subtly enforce a nationwide 55 mile per hour limit (originally conceived as an economic measure to save gas, but later re-characterized as a safety program) via financial coercion, then allowed 65, then stopped caring as much. Nowadays almost no states outside the Northeast have regular interstate speed limits set that low - 65mph and 70mph are the most common in the Eastern half, while 75mph is the most common limit in the Western half. One state (Montana) even tried eliminating fixed daytime speed limits completely, but this particular experiment in libertarianism was ended after some drivers severely abused the "safe for current conditions" requirement and the courts held that it was too subjective to be enforced by law. Presently, the fastest daytime speed-limit in effect is 85mph, on one divided highway in Texas ^note  State Highway 130, a toll road that runs from San Antonio to Austin that crosses extremely sparsely inhabited land. Some places have a different (slower) speed limit at night, and/or another different (slower-than-normal-daytime) speed limit for heavier vehicles such as trucks or vehicles with a trailer hitched behind them.

Licensing requirements vary from state to state but are similar in general outline: Licenses are available relatively young (typically at age 16) and "Learners Permits" that allow users to begin instruction are often available at even younger ages, 14 or 15 depending on the state. Many American high schools offer driver education as part of their standard or supplementary curriculum, and attaining a driver's license is often seen as a teen rite of passage, their "ticket to freedom" (or at least the mall), though more and more states now mandate some form of limited or graduated license for drivers below the age of 18 (Example: A driver with a provisional license may be prohibited from driving at night, or prohibited from carrying non-family passengers under age 18, and in most instances, being pulled over and having any alcohol in your blood is an immediate loss of license. New York City bans anyone under 18 from driving within the city limits.) A basic operator's license (the exact terminology varies state to state) typically authorizes the licensee to operate any automobile or light truck up to 26,000 lbs (which is not coincidentally the size of a typical rental moving van) and is often a prerequisite for more advanced licenses.

Drivers of "big rigs" (anything over 26,000 lbs, including the iconic "18 wheelers") must qualify for a commercial driver's license, or CDL. Basic CDL requirements are more or less uniform across all states since they fall under the federal government's authority to regulate interstate commerce, though states are allowed to impose additional requirements (often called "endorsements") over and above the basic federal requirements for things like special vehicle equipment (such as air brakes or semi-trailers) or the transportation of passengers or hazardous materials. Given the potentially tragic consequences of an inexperienced driver or one on the verge of a sudden heart attack behind the wheel of a massive vehicle a CDL normally requires the holder to both maintain certification (either through testing or experience) and pass an annual health check as well (though the latter is sometimes honored "in the breach".) Several schools exist across the U.S. to train people to drive these vehicles, help them get the appropriate licenses, and get them jobs in the field.

Motorcycles usually require their own class of license, either as a separate license or as endorsement, but otherwise are treated like cars at least as far as the law's concerned. Motorbikes (a motorcycle with an engine with less than about 40 horsepower) are treated with less seriousness than motorcycles; some states allow anyone 16-or-older to ride a motorbike, or require a driver's license. The requirement to treat cycles the same as cars means that the guy on a decrepit Honda in front of you IS entitled to the whole lane, and not just the small bit of it his motorcycle occupies, (except if two riders choose to do so they may share a lane), and other vehicles must yield to him when he has the "Right of Way" (assuming, of course, that they see him. A smart motorcyclist knows the laws of physics will always trump the laws of traffic, he stands to lose the most in any collision, and being "dead right" will be a very limited consolation to his heirs). Some motorcyclists object to mandatory helmet laws, others don't, and states vary; anecdotal evidence abounds of a motorcyclist carrying a helmet while in one jurisdiction, only to put it on before entering another. Some states also have special laws for motorcycles to improve the flow of traffic: Massachusetts, for example, allow motorcycles to maneuver through traffic jams by making use of the space between cars, as long as they can do so safely. (Drivers in the US learn to expect motorcyclists to do this as a rule, usually at full speed, whether or not it's officially permitted.)

Mandatory seat belt laws can be similarly seen as controversial: Some people consider seat belts a public safety issue, some people consider them a matter of personal freedom, and still others believe stupid people should die. That hasn't stopped most states from requiring their use (nearly all mandate it for the driver ^note  The only exception being New Hampshire, which does not mandate seat belts for all adults who are age 18 and older , most states also mandate it for passengers), in part because the federal government offers significant financial incentives for them to do so. Most people, outside of fanatical libertarians, view wearing of seat belts as simple common sense. The controversy comes with whether failing to "buckle up" is considered a "primary" offense (meaning you can get stopped for it) or a "secondary" offense (meaning you can only be cited for it after you've been stopped for something else, like speeding or a busted taillight) depends upon the state, though most states do mandate some form of safety restraint for children.

Despite what you may have seen on television, Americans generally tend to obey their traffic laws, and US traffic accident rates tend to be among the lowest in the world, particularly on the basis of accidents per miles (or km) driven. Speeding is probably the most common violation in the US (and probably anywhere) with "shaving" traffic lights a close second. Conventional wisdom, and common sense, suggests going with the flow of traffic, and if everyone else on the road is flying along at 5-10 MPH over the limit (pretty common on non-urban highways in most states, and almost de rigeur on the Interstate Highway System) then obviously you should do so as well... an argument which may or may not cut much ice with a police officer. Or a judge. The general rule seems to be that if traffic everywhere is going over, you go at the speed that is necessary to maintain a smooth flow. In fact, driving too slowly can get you pulled over and/or ticketed for obstructing traffic, as it is likely to result in exasperated drivers doing reckless or dangerous things to pass you, and (while obviously also illegal) can potentially make you a victim of road rage.

But sometimes the police do understand. In Virginia, on highways where the speed limit is 55, every single speeding case the state troopers bring in court never give a speed higher than 74 miles per hour. The reason for this is that driving 20 miles over the speed limit there is automatically "Reckless driving," a very serious crime, so the troopers always write the driver up for going 19 miles above the speed limit.

Still, this doesn't stop law enforcement from trying various ways of slowing down the pace. Speed cameras are becoming increasingly common, though they are still not nearly as common as in Europe: a section of road is set to allow cars to have their speeds checked, and if one is too fast, a photograph is taken of it (and its number plate), allowing someone to send the car's owner a fine. This is, of course, controversial (especially to the recipients of the tickets) in large part because historically it is the vehicle driver (who may not necessarily be the owner) who is responsible for operating the vehicle safely. Those in favor call it a public safety measure; those against call it a cheap way of raising cash (There's also an oft-quoted legal precedent against speed cameras, namely, the right of the accused to confront their accuser. While most recipients of speed camera tickets don't invoke this, those that do tend to find their cases dismissed, as arguing the point is more costly and time-consuming than the ticket would be worth.) A similar phenomenon are the "red light cameras" used for stoplights in many areas too.

Likewise, recent tax incentives for hybrid and electric vehicles notwithstanding, the US Government does not tend to use tax policy to manipulate vehicle design or driver choice, by say, encouraging diesel fuel as in Europe or ethanol like Brazil, or penalizing engine displacement as in Italy. Much of this is because a large number of cars and trucks that would be considered "gas guzzlers" are made in the U.S., and the United Auto Workers (or UAW, the union that represents most American employees of the "Big 3" — GM, Ford, and Stellantis) has a lot of influence in Washington. (Prior to 2004 SUVs were considered trucks and subject to less-strict standards on emissions and fuel economy, though, which played a big role in their popularity.) As a result, fuel costs primarily stem from market forces and Americans choose to drive vehicles scaled to fit American roads and driving conditions and the few urban microcars that can actually meet the US's fairly stringent crash safety and emissions standards have achieved very little market share. Finally, given the relatively large amount of driving they do, Americans tend to want their vehicles to be reliable: It was reliability that allowed Japanese (and later Korean) brands to capture such a large percentage of U.S. auto sales just as it was the perceived lack of reliability that, more than anything else, caused virtually all French, British and Italian makes to succumb to American and Japanese brands and leave the US market.

Finally, if you're visiting America and decide to drive someplace touristy, please measure the distance first (and don't forget that 1 mile = 1.6km). Therefore, if you are used to driving across your own country as a day-trip, it can be a bit startling to find out that crossing the United States by car can take up to four days depending on the direction you are going, the roads you are driving on, and how hard you push yourself. There are many stories of tourists (usually German, for some reason), trying to drive from New England to the Rockies "for the weekend". This would literally be "driving for the whole weekend": the trip from Boston to Denver (at posted speed limits) takes 32 hours, non-stop, as in, that doesn't even allow for re-fueling stops, let-alone bathroom breaks or sleep. And a drive from New York City to Los Angeles? It's about as long as a trip from Helsinki, Finland to Lisbon, Portugal.