10 Things You Might Not Know About the U.S. Interstate System

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istock

Inspired by the network of high-speed roads he saw in Germany during World War II, Dwight D. Eisenhower championed the passing of the Federal-Aid Highway Act of 1956. The law funded the first 41,000 miles of paved glory that made up the early U.S. interstate system, which now boasts 46,876 miles and runs through all 50 states. (Yes, even Alaska and Hawaii.) Prepare for your next cross-country (or cross-town) road trip with the following facts.

1. IT TOOK 17 YEARS TO CREATE AND FUND THE IDEA OF THE INTERSTATE.

Two members of the U.S. Bureau of Public Roads presented a report to Congress in 1939 that detailed the need for a non-tolled road system in the U.S. The Federal Highway Act of 1944 allowed for development of a 40,000 mile National System of Interstate Highways, but it didn’t provide any method of funding, so it went nowhere. It wasn’t until the act of 1956 that funding was finally allocated to its construction.

2. PEOPLE FIRST LOVED, THEN HATED IT. 

When the Interstate Highway Act was passed, most Americans thought it was a good idea. But when construction started and people, especially in urban areas, were displaced and communities cut in half, some started to revolt. In the 1960s, activists stopped construction on highways in New York, Baltimore, Washington, D.C., and New Orleans, which resulted in several urban interstates becoming roads to nowhere.

3. EVERY STATE OWNS ITS PORTION (INCLUDING THE POTHOLES) …

This means the state is responsible for enforcing traffic laws and maintaining the section of highway in its borders. Currently, the “largest pothole in the country” award has been claimed by this section of I-75 outside Detroit. 

4. … EXCEPT FOR ONE (FORMER) BRIDGE.

The Woodrow Wilson Memorial Bridge (I-95/495) that crossed the Potomac River into Washington, D.C. used to be the only part of the interstate system owned by the Federal Highway Administration. But issues over it being too small led to the creation of a new, bigger, taller bridge. As for the old one? It was destroyed, in part by people who won a contest for having “the toughest daily drive.”

5. THE STATES SET THE SPEED LIMITS.

However, in the early 1970s, all 50 states set their speed limits to 55 mph. A clause in the Emergency Highway Energy Conservation Act signed into law by Richard Nixon dictated that if a state did not set its highway speed limit to 55 mph, that state would lose its federal highway funding. 

6. THE SIGNS ARE TRADEMARKED.

The red, white, and blue shields used to designate interstate numbers are trademarked by the American Association of State Highway Officials. The original design for the shield was drawn by senior traffic engineer Richard Oliver of Texas and selected out of 100 entries in a national design competition in 1957. 

7. INTERSTATES AND HIGHWAYS WITH THE SAME NUMBER CANNOT RUN THROUGH THE SAME STATE.

The numbering system used for interstates is intended to be the mirror opposite of the U.S. highway system, so drivers won't be confused about whether to take Highway 70 or Interstate 70. For example, I-10 runs through southern states east-west (as all major even-numbered interstates do; odd-numbered interstates run north-south), while Highway 10 runs through northern states. Because I-50 would run through the same states as Route 50, the number will never be used. 

8. I-99 DOESN'T FOLLOW THIS SYSTEM, BUT THAT'S NOT THE FEDERAL HIGHWAY ADMINISTRATION'S FAULT.

According to the Federal Highway Administration's numbering system, Pennsylvania's former US 220 should have been named something like I-876 or I-280. But Representative Bob Shuster wanted a catchier moniker for it. According to The New York Times, as a child he was fond of the No. 99 streetcar, which he used as his inspiration for the road's tag. 

9. THE INTERSTATE IS PART OF THE U.S.' ATOMIC ATTACK PLAN. 

A major concern during Eisenhower’s presidency was what the country would do in the event of a nuclear attack. One of the justifications for the building of the interstate system was its ability to evacuate citizens of major cities if necessary. 

10. THERE ARE NO DESIGN RULES DICTATING THE SHAPE OF ROADS.

A major myth of the interstate system is that one out of every five miles is straight so an airplane can land. While this has happened, there are no rules or regulations that require such a design. Also, there are no requirements for curves to be designed into a highway to keep drivers awake. However, the Federal Highway Administration does admit that this is a perk of winding roads.

10 Common Road Hazards and How to React to Them

iStock.com/LeManna
iStock.com/LeManna

James Solomon has been a defensive driving expert with the National Safety Council for 34 years. He has taught driving courses for 47 years. And one of the best pieces of advice he can give has absolutely nothing to do with an automobile.

“If it sounds like there might be inclement weather the next day,” Solomon tells Mental Floss, “set your alarm an hour early. You’ll have enough time to get up, clean your car off, and drive slowly.”

That's especially sound advice for a good part of the country, as the winter season means more driving perils, including poor visibility, snowbanks, and ice. Other road hazards like fog, deer, and road-hogging commercial trucks never seem to take a break. For some practical advice on what to do in these situations, we asked Solomon to break down 10 common driving obstacles and the best ways to cope with them. Here’s what he had to say.

1. DRIVING ON ICY ROADS

A sign warns of a slippery road ahead
iStock.com/trendobjects

Nothing can jolt a driver like the sudden loss of control of their automobile after hitting a slick patch of pavement. While some ice is noticeable, “black ice”—which occurs when ice has thawed and re-frozen—can be hard to spot.

What to Do: If your car goes into a skid or loses traction, the best thing to do is remove your foot off the accelerator. “You don’t want power of any kind going to the wheels,” Solomon says. If you have standard braking, keep your foot entirely off the brake. If you have an automatic braking system (ABS), which is pretty much standard in most newer cars, you want to push the pedal down and wait for the car to regain traction. Don’t pump the pedal: The ABS can pulsate the brakes faster than your foot can.

You also want to turn the wheel in the direction you want the front of the car to go. “Once the vehicle begins to straighten out, counter-steer in the opposite direction,” Solomon says. “Steering and counter-steering should be done three to five times while braking.” Keep doing it until you feel the wheels grip the pavement.

2. GETTING STUCK IN A SNOW BANK

A car tire is stuck in snow
iStock.com/JaysonPhotography

After a heavy snowfall, you might return to your car to find the wheels surrounded by snow. As they spin, they can’t find any grip on the slick powder, and you’re going nowhere fast.

What to Do: A little foresight is best here. Solomon advises you keep a shovel, brush, and a pair of traction mats in your trunk. (Kitty litter may also work for traction, but the mats are reusable.) If you’re stuck, make sure you have enough room to move the car forward and backward and that there isn’t any snow blocking the exhaust pipe. Clear the snow away from the wheels and try moving forward or in reverse. If that doesn’t work, put the mats under the front wheels (for front-wheel drive) or under the back wheels (for a rear-wheel drive). Once the wheels are on the mat, try turning to get away from the snow. Solomon cautions to watch out for passing traffic, as other drivers might have trouble spotting you.

3. DRIVING IN HEAVY RAIN

Heavy rain falls on a car windshield
iStock.com/Willowpix

People don’t always think of a torrential downpour the same way they think of a snowstorm, but heavy rain can impede visibility and cause hydroplaning, where the wheels come off the pavement and onto the surface of the water, causing drivers to lose control.

What to Do: For any type of driving in the rain, make sure your tire tread depth is no less than 5/32 of an inch, and preferably much more: new tires typically start around 10/32 of an inch. A worn tire at 2/32 of an inch is asking for a crash, as the stopping distance of a car is increased and traction is reduced. You can estimate depth by sticking a penny upside-down in the tread: If the top of Lincoln's head is visible, it's time for new tires.

Solomon also recommends changing your wipers regularly: a more durable winter blade, a March rain blade, and another August rain blade. And make sure they’re not being held back by your cleaning habits. “If you’re going through car washes and they’re using wax, the wipers are going to be sliding over that,” he says. A wax stripper found at automotive stores can erase that residue, clearing your windshield and allowing your wipes to make better contact with the glass. “The first time you spray it on, you’ll get a crusty, filmy look, which is all the wax you’re dissolving.”

If your windshield is clean but the rain is still obscuring your vision, then you’re probably driving too fast for the wipers to clean the glass efficiently. If it’s that bad, pull over to the side of the road and wait for the downpour to ease up. But never, ever park under an overpass. “You’re a sitting duck there,” Solomon says. “You’re stopped with a guardrail or pillar next to you and your transmission locked. If you’re struck by another vehicle, there’s no place for your car to go. That’s a huge amount of weight hitting you.”

4. BLINDED BY GLARE

A driver observes sun coming through the car windshield
iStock.com/xijian

Winter or summer, the sun sometimes has a way of shining through your windshield just the right angle to effectively blind you. Keeping a pair of sunglasses handy is the best solution, but there are a few other ways to cope.

What to Do: “All cars come equipped with a sun visor,” Solomon says. “The problem is when people pull it down and the edge is pointed at your nose. In a collision, your face will slam right into it.”

Instead, pull the visor down and then push it all the way toward the windshield, then slowly bring it forward until it blocks the sun. (The bottom should still be pointed away from you and toward the windshield. Solomon also keeps a baseball cap in his car so he can use the bill to block the sun without obstructing his view. If glare is coming from the left-side window, remember that most visors are detachable on one end and should be able to pivot and block peripheral light.

5. A TIRE BLOWOUT

A car tire rests on the ground after a blowout
iStock.com/batuhan toker

While some tires may pick up a stray nail or sharp object and deflate slowly, others lose pressure suddenly. If you’re down to three good tires, you’re no longer in a position to drive safely on the road.

What to Do: “The big mistake people make with a sudden loss of pressure is to hit the brake and stop to save the tire,” Solomon says. “But if the air went out that quick, the tire is gone.”

Instead of trying to salvage the tire, focus on getting off the road. If you’ve lost pressure, you want to continue traveling in a straight direction until you can stop. If the tire’s sidewall blows out, the car will probably move in the opposite direction of the break. A blown front right tire will cause the vehicle to drift left, for example. “Drive with two hands on the wheel, put your emergency flashers on, check your mirrors, and get over to the right shoulder of the road if at all possible,” Solomon says. “If you’re in a skid, you may have to keep your foot on the accelerator a little bit to force the wheel to move forward.”

Check your tire pressure at least once a week, especially in winter, when the pressure can drop. But if it suddenly turns warmer, make sure to let the air escape. An overinflated tire can cause the side tread to leave the surface, leaving only the center tread in contact with the road. Your owner's manual or a label inside of the driver's side door will tell you the correct tire pressure for the vehicle.

6. BRAKE FAILURE

A foot presses on a brake pedal
iStock.com/Kameleon007

The ability to stop a vehicle is probably the most important function of all, and when it fails, it’s easy for panic to set in. If you’re pushing the brake pedal and nothing is happening, you need to take immediate action.

What to Do: First, don’t assume your brake lights are still working. “Hit your emergency flashers and pump the brake quickly three or four times,” Solomon says. If that doesn’t work, you need to take a lightning-fast look at the floor mat. It’s not uncommon for the mat to get bunched up behind the brake pedal, making it hard to move. Dislodging it while the vehicle is in motion is dangerous, so prevention is key: Make sure your mat is the right fit for your vehicle, is snapped in place if that option is available, and that you haven't stacked mats on top of each other.

If that looks clear, then go into neutral. “You want to deprive the car of forward motion,” Solomon says. Once you’re in neutral, take your emergency brake—typically a lever with a button on the side console—and begin pumping it up and down. (Some cars have an electronic brake that only requires a button push. Read your owner’s manual.) The brake should lock up the rear wheels and allow the car to come to a stop.

7. SOMEONE IS TAILGATING YOU

A car is seen in a rearview mirror
iStock.com/Ryan Herron

Having a vehicle riding too close to your rear bumper can be a nerve-wracking experience. If you need to brake suddenly, the car is likely to collide with yours. If you honk, flash your lights, or make an insulting hand gesture, you run the risk of antagonizing someone who is already behaving irrationally.

What to Do: “What I want to do is encourage them to pass me,” Solomon says. “If I can, I’ll signal, move to the right-hand lane, and that will generally take care of it.” If you can’t, wait for an intersection so you can make a right turn or drive into a service station. Just don’t engage them: “There’s nothing you’re going to do to stop them from tailgating you. Tricks like tapping your brakes—well, no, you’re dealing with an aggressive person and you’re only going to make them more angry.”

8. GETTING STUCK BEHIND A COMMERCIAL TRUCK

Commercial trucks take up both lanes of a road
iStock.com/esemelwe

Feeling the rush of wind that accompanies a passing 18-wheeler can give you a healthy respect for these road behemoths. If you’re behind one, they can make it difficult to see what’s ahead. If you’re behind two, or in the middle of them, you might start to feel trapped.

What to Do: It’s important to determine whether the truck driver is aware of your existence before you attempt to pass. “If I can’t see the driver’s rear-view mirror, he can’t see me,” Solomon says. “If I can see their reflection, then they can probably see me.”

A good rule of thumb is to add an extra second of following distance to the recommended three seconds for most drivers. (Following distance is the amount of time it would take for your car to pass a landmark, like a roadside sign, after the driver in front of you has passed it.) In bad weather, Solomon says to increase it to seven or even 12 seconds to avoid debris and snow hitting your windshield.

If you’re stuck between trucks on a three-lane highway, decrease your speed by about five miles and let both trucks overtake you. Eventually, one will go faster than the other, and you’ll be able to choose your lane. The same holds true for buses.

9. DRIVING IN FOG

A road is covered in fog
iStock.com/Cha_DZ

It makes for fine gothic horror movies and ‘80s music videos, but fog is otherwise a hazard. Driving through it can reduce visibility in a manner similar to a bad snowfall.

What to Do: Your instinct might be to put on your high beams to better illuminate the road ahead. Don’t. “You’ll wind up seeing less,” Solomon says. “The beam shines further into the fog and reflects off the water particulates, shining the light right back into your eyes.” Instead, keep your lights dim and slow down.

10. DEER CROSSINGS

A deer crossing sign is posted next to a road
iStock.com/jimkruger

Back roads can often be nestled directly in the path of deer, animals that have no understanding of passing traffic and can appear out of nowhere. Even if you manage to avoid hitting one, a yearling could be nearby, ready to do serious damage in a collision. In this case, responsibility falls strictly on you to avoid an accident. “Deer don’t look both ways before crossing,” Solomon says.

What to Do: If you’re in deer country and it’s dark, you can try flashing your headlights to get a deer’s attention. They might take it as a sign to hang back. If you see a deer up ahead, take your foot off the gas to slow your speed, then flash your lights. This may make it run off the road. If not, it’s time to brake: Swerving off the road at highway speeds is risky and can cause serious injury to the driver and passengers. Always read the road ahead. You don’t want an animal that large smashing through your windshield. And as bad as it may sound, it will be even worse if they survive the impact. “If it’s not dead, it will be kicking, with sharp hooves and antlers,” Solomon says.

Get to the side of the road immediately and exit the car. If traffic is high or the road is narrow, go through the passenger’s side door. Above all, take the deer crossing signs seriously and go slow. “When you see those signs, it wasn’t because the state or county had some extra money and thought they’d go put them up,” Solomon says. “It means there have been problems with deer crossing the road.”

5 Holiday Foods That Are Dangerous to Pets

iStock/svetikd
iStock/svetikd

One of the best parts of the holiday season is the menu of indulgent food and drinks that comes along with it. But while you enjoy that cup of spiked hot cocoa, you’ve got to be careful your dog or cat doesn’t nab a lick. Here are five holiday treats that are dangerous for your pets, according to Vetstreet.

1. COFFEE

Any coffee lover will agree that there’s nothing quite like an after-dinner cup of joe on a cold night. But pups, kitties, and other pets will have to sit this tradition out. Caffeine can prompt seizures and abnormal heart rhythms in pets, and can sometimes be fatal. Other caffeinated drinks, such as soda or tea, should also be kept away from your four-legged family members.

2. BREAD DOUGH

We know the threat that bread dough poses to the appearance of our thighs, but it’s much more dangerous to our furry little friends. Holiday bakers have to be careful of unbaked bread dough as it can expand in animal stomachs if ingested. In some dogs, the stomach can twist and cut off the blood supply, in which case the pup would need emergency surgery.

3. CHOCOLATE

Cat and dog in Santa hats chowing down on plates of food
iStock/TatyanaGl

A little chocolate never hurt anybody, right? Wrong. The sweet treat can cause seizures and even be fatal to our pets. Darker chocolate, such as the baker’s chocolate we love to put in our holiday cookies, is more toxic to our pets than milk or white chocolate. The toxic ingredients include caffeine and theobromine, a chemical found in the cacao plant.

4. MACADAMIA NUTS

Macadamia nuts, which are a common ingredient in holiday cookies and often put out to munch on as an appetizer, can be toxic to dogs. While poisoning might not always be easy to detect in a pet, clinical warning signs include depression, weakness, vomiting, tremors, joint stiffness, and lack of coordination.

5. ALCOHOL

Think back to when you first started drinking and how much less alcohol it took to get you tipsy, because you likely weighed less than you do now. Well, your pet probably weighs a lot less than you did, even back then, meaning it takes much less alcohol to make them dangerously sick. Keep those wine glasses far out of reach of your pets in order to avoid any issues. Well, maybe not any issue: We can’t promise that this will stop you from getting embarrassingly drunk at a holiday party this year.

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