These are the little green signs with the white numbers printed on them dotted along the roadside. Mile markers on interstate highways can also help you determine which direction youre going. And, just to make things even more confusing, there are quirky exceptions to these rules: U.S. How are mile markers used in the United States? Highway.). You will find primary routes run in the 1s to 10s range. The letters indicate the county. Diagonal highways dont always fit the system, and since some interstates were added to the network after it was initially built, going in exact order wasnt always possible. Thought we'd have no problem with road side assistance determining our location. This cookie is set by GDPR Cookie Consent plugin. So, mile marker numbers always get larger as you travel east or north. That's best you were able to visit the Corvette Plant. The highway routes and interstate numbers can actually help you identify where you are in the U.S. You may not fully clear on the difference between a route and an interstate. They have three digits, hence the nickname 3di for 3 digit interstate. Your membership is the foundation of our sustainability and resilience. Please log in again. On east-west routes, the numbers begin on the western state border and increase as you travel east. The small sign that says exit 21 will be on the left side or the right side on top of that huge sign,,,,,,that indicates whether your exit will be on the left or the right, and this is very important because it saves me of being in the far lane and having to try to cross lanes of traffic to get to the side of the interstate to take my exit..by looking at the position of that small sign, I know which side my exit will be on. If you continue to use this site we will assume that you are happy with it. Routes and Interstate Highways. For example, this marker is Monterey County (MON). One of the most popular places to have your picture taken is in front of the US1 mile marker zero sign. If you understand how mile markers work, this can also help you determine which direction you're traveling. A transcontinental permanent fixture on Mother Nature, spanning the New World, whereby travelling salesmen, anti-prohibitionist entrepreneurs and wanderlusting dads dragging their families along alike could roam from state to state with nothing between them and the open road but the wind through their toupees. Mile number one is always in the west or the south. We're so excited your classes are WONDERing with us today! Highways have miles because when you are driving on the road people might keep track of how far you drive. As in the Atlantic Ocean, New York City and Florida. Thank you and have a nice day It is a main highway between Houston and Austin and is a cutoff for travelers wanting to bypass San Antonio on I-10. On most interstates, mile marker numbers begin at the south state line on north-south routes and increase as you travel north. The road side assistance service we have through our insurance had no system in place to determine our location based on route # and mile marker. 20142023 National Center for Families Learning, http://wonderopolis.org/wonder/why-do-highways-have-mile-markers, National Center for Families Learning (NCFL). One is the use of kilometers on Interstate 19. They have three digits, hence the nickname 3di for 3 digit interstate. The login page will open in a new tab. Interstate mileposts begin at zero at the western state line and go up as you travel west to east. Why do mile markers go from west to east? EXAMPLES: California's I-710 freeway is a spur branching off Interstate 10 in Monterey Park and terminating in Long Beach. If its after lunch, wherever the Sun is, thats West. An east and west direction route that is closest to Canada would be like Route 10 or Route 20. Blocksma, Mary. All of the images can be enlarged by clicking on them. These cookies ensure basic functionalities and security features of the website, anonymously. These cookies track visitors across websites and collect information to provide customized ads. Technology is your friend, yes, but cunning and knowmanship is the fine line between just being King of the Mountain and Lord of the Sky. US Highway 82 runs from Alamogordo, New Mexico, to Brunswick, Georgia. For the most part, states follow the Interstate and U.S. Highway patterns of assigning odd numbers to north-south routes and even numbers to east-west routes, but as always there are exceptions. Protect pedestrians and vehicles at busy intersections. The counting always begins at the state line in the south (for north-south routes) and in the west (for east-west routes). WRONG! Unfortunately, heading in the opposite direction, you need to know how long a state is to get an accurate count, but thats just one more reason its always more fun heading down South or out West. Sometimes states just refuse to cooperate (ahem, damn you the South!) In the photo, its CA Hwy 1. Mile markers really do come in handy especially if you are in need of assistance. North-south routes are assigned odd numbers, with the numbers growing larger from west to east; east-west routes are assigned even numbers, with the numbers growing larger from south to north. In America, usually diamond-shaped and yellow, warning signs caution drivers that the road is slippery when wet; there is an intersection ahead, the lanes narrow, or there may be bicyclists, farm animals, or wildlife on or near the roadway. Interstate 90 crosses the USA from Seattle, Washington, to Boston, Massachusetts. 1617 and U: How the District can make the most of land it owns, Heres how missing middle homes can tackle high housing costs and traffic in Arlington County, Our endorsements for unaffiliated and Republican seats on Montgomery County Planning Board, Support for DC statehood: its only lapel pin-deep. New York State Roads - I-90 Exit List. "Highway Numerology Muddled by Potholes in Logic." Performance cookies are used to understand and analyze the key performance indexes of the website which helps in delivering a better user experience for the visitors. Many states have added supplemental reference markers that indicate distance in fractional miles (tenth, quarter, half, etc.) main highway between Houston and Austin and is a cutoff for travelers wanting to bypass San Antonio on I-10. Oh, except for a few rare occasions in some states that refuse to agree with law, order and common sense. These routes are designated with the number of the main route and an even-numbered prefix. But did you ever stop to think how you'd tell them where you are? 348. In traffic engineering, the late merge or zipper method is a convention for merging traffic into a reduced number of lanes. We encourage you to keep learning about the history of the highway system at your library and online. If you can tell them you're only about a quarter-mile past mile marker 23, though, you'll probably get the assistance you need fairly quickly. Wonder What's Next? A yield sign means, you do not have the right of way. Head South. As a result, as you travel east or north, mile marker numbers grow larger. Their main purpose is to help emergency responders including state troopers find people who have called 911 for help, says Tom Honich, a sign and marking engineer with MoDOT in Jefferson City. Another example would be if you were at the intersection of I-5 and I-90, that would place you in Seattle Washington. Example would be U.S. 20B, B would stand for Business. Telling them you're on Highway 37 near the big oak tree with the funny bend in it probably isn't going to help all that much. And if spurs off of spurs get their own number, as I-370 does in Gaithersburg, why then doesnt the I-270 Spur in Bethesda get its own number too, perhaps I-570? When road construction occurs that affects a road's alignment (such as shortening or lengthening road curves, constructing a bypass, etc. You can easily fact check why are there mile markers every .2 miles by examining the linked well-known sources. If everyone reading this gave just $5, we could fund the publication for a whole year. Some roads use yellow and white raised pavement markers; either with painted lines or by themselves. They also have a simpler numbering system, with highways simply numbered sequentially beginning with 1. New York mostly follows suit. Why is I-95 named I-95? Ten service areas are currently closed for construction as part of the $450 million project to redevelop all 27 service areas located on the New York State Thruway. Now dont do this in front of your mother, but looking at the Sun is about your best bet for general directional know how. A mile-marker exit number system lets drivers know how far they need to travel to reach their desired off-ramp. Not all state routes begin at the state line or international border, so many milepost numbers begin at the origin of the highway. We hope you are having fun WONDERing with us! It does not store any personal data. Though there is more science involved than just that. Have fun WONDERing! To prevent duplication within a state, prefixes go up. That having been said, of course, some basic skills will come in exceptionally handy. Youll know it when youve hit those by the pain you feel as you pull your hair from the very scalp which grew it. 2/East Greenwich/West Warwick. Interested in sharing Wonderopolis every day? Have you checked out Wonder #822-- Do You Know Who to Call in an Emergency? Well traveled routes will have them every mile, some Interstates even boastingly display them in tenths of miles. Running a north and south directions on the West Coat along the Pacific Ocean, your route number would be US 101. :), Great point, Mrs. Power and Mrs. O'Donnell! 1 What are mile markers and why are they useful? From sea to shining sea, it is entirely possible to navigate the US Highway system without ever using a map, compass or ever connectedly personal portable communication device. Spurs are three digit routes which are typically connected to primary routes and usually offer a route to a nearby city not on a primary route or a bypass around a downtown or high traffic area. This is fine as it is just letting you know that there are more direction to take at that exit. These can have three-digit spurs, though H201 is the only such example. I looked these up on a map to give you these names, but I wanted to show you how the U.S. grid works. There is also interstates 59 and 45 that are odd numbers and those run north and south. Some smaller markers are placed at every 0.1 statute miles of the highway. As with most things, there are definitely exceptions to the rule! See it's a no brainier oh and right next door to the Corvette Museum. In the United States, exit numbers are assigned to freeway junctions, and are usually numbered as exits from freeways. Contact. Back country US Highways will spread them out as thinly as one every twenty miles or so. __CONFIG_colors_palette__%s__CONFIG_colors_palette__. The farther N. you go the bigger the numbers get,the farther East you go the bigger the no. What are mile markers and why are they useful? On east-west routes, the numbers begin on the western state border and increase as you travel east. An example of a detour is a side road that drivers must go down when the main road is closed. 14B. While the interstate is closed, the ramps from I-435 South to I-70 East and I-435 North to I-70 west will be demolished. NORTH-SOUTH EXAMPLES: US Highway 1 runs from Fort Kent, Maine, to Key West, Florida. So why do mile markers I-90 in NY go down as you drive east? Every once in a while, you notice a little green sign with a number on it. Mile, any of various units of distance, such as the statute mile of 5,280 feet (1.609 km). On most interstates, mile marker numbers begin at the south state line on north-south routes and increase as you travel north. Do you remember your first lost tooth? How do I delete pictures from my iPhone that won t delete? Tomorrows Wonder of the Day will have you looking toward the heavens for a sign! So if you knew that Texas was 877.5 miles across on I-10 and you start at 1. New York: Penguin Books, 1989 (pp. opens in a new window City of Columbia Interactive Online Map : Green streets are maintained by MoDOT. Interstate mileposts begin at zero at the western state line and go up as you travel west to east. Get. If you were closer to Mexico, your Route numbers would be something like US 80 or US 90. For north-south routes, the lowest numbers begin in the west, while the lowest numbered east-west routes are in the south. These cookies will be stored in your browser only with your consent. Houston Texas is a great example of how this works. 6. Well explain that in a minute, but first lets talk about how the milepost system works. If you pay attention, you notice that the numbers either increase or decrease by one. Below are some signs that you will find on the interstates and highways. :), Great WONDERing, Alan! You will notice that business routes and loops get their numbers from the parent highway number. Thanks for your patience. Remodeled rooms 3 star hotel experience. Interstate I-10 practically runs coast to coast. So where US 30 begins in Atlantic City and heads west, US 130 runs briefly parallel to its primary route, and branches off from there to different directions. Interstate I-10 practically runs coast to coast. Play roadway math! Keep in mind that for reasons of practicality, highways swerve and sway to avoid downtown traffic, connect to nearby routes and generally avoid plunging off of cliff sides, but big picture thinking here, this rule holds true. :), Great point, Wonder Friend AJ! Mileposts vs. Mile Markers Catawba County Catawba County We use cookies to ensure that we give you the best experience on our website. The number of digits tells you whether an interstate connects multiple metro areas, or exists solely within a single metro area. So where US 201, 301, 401, etc. But the smaller two-digiters can repeat as long as theyre far apart from each other. Whats the difference between a highway marker and a milestone? Snopes and the Snopes.com logo are registered service marks of Snopes.com. :). Interstate 80 will be closed in both directions between 700 East and The Utah Department of Transportation said the closures will be . We hope you'll continue to Wonder all weekend long! Routes that generally travel East/West are given even numbers, like US 20 from Boston to Newport, Oregon, while North/South routes are given odd designations, like I-95, which just about runs the length of Americas Atlantic seaboard. Mile markers can tell you what direction you are going. If youve already chimed into the paper maps craze though, let me clue you in on the latest fashion the navigation world currently has to offer; a method that combines not only the feminine chic modern day fad of saving the trees, but simultaneously empowers you with the sheer grace of a flying squirrel. Red markers are always on the mainland side. How to Read a California Mileage Marker. What purpose could a small green sign with the number 137" on it possibly have? And MA doesn't do their exit numbers by mileage (which is genius!). If you understand grids the better, but even if you dont, the above can tell you what area of America you are in by the numbers. All mm(mile marker) numbers start in the West and the South. Great Nightly rate, weekly and monthly rate. If you ever have to call 911 on a state highway or interstate and youve paid attention to the mileposts, emergency crews will be able to find you faster. Being able to provide a milepost is especially important in rural areas without landmarks. This one is at mile 58. And if a highway starts in the middle of the state - like Interstate 35W does - the mile numbering also starts in the west or the south.. How are major interstate highways identified? Exit numbers also typically correlate to milepost numbers. Exit numbers can help track you location or your pace. Great work, Wonder Friends! Lets get down to the details, shall we. I-10 runs across Houston, which is an even number for east and west. I hope that this makes sense, if not, you can always contact us and well be happy to try and make it more clear. Left, 1.1 miles. Spurs and connectors that only intersect once usually get odd first digits. With US Highways and the Interstate, they come with clear rules. -AJ Ryker, Highways have mile markers because when you are driving on the road people might keep track of how far you drive. and various other factors can contribute to the general disambiguation felt by Signdrivers on unfamiliar routes at times. Great work, AJ, it's important to remember what to do in an emergency. TECHNOLOGY Transportation. Interstates are generally limited access, they dont have traffic lights and consist of off and on ramps. He's on Instagram. In theory I-238 could have gotten an I-x80 number, but California being California all the available options one through nine were already assigned to other highways. Go for a drive on the highway with an adult. The interstate travels through the Deck Park Tunnelin the heart of Phoenix at milepost 145 and continues on to Tucson, where the milepost number hits 255. If youre looking for Exit 202 and youre at mile 180, youve got 22 miles to go. We appreciate you WONDERing with us and leaving a comment! The numbering of Arizona state routes is similar. It runs for 17.62 miles through Anne Arundale County in Maryland. North-south routes are assigned odd numbers, with the numbers growing larger from west to east; east-west routes are assigned even numbers, with the numbers growing larger from south to north. Where are the milepost markers on the road? This one is at mile 58. General Sense of Direction. The Federal-Aid Highway Act of 1944 was enacted by Congress, and in 1947, the first 37,700 miles of road were selected. How do you remove scratches from solid surface countertops? These cookies help provide information on metrics the number of visitors, bounce rate, traffic source, etc. For example, I-395 connects to I-95, and I-270 connects to I-70. Theres a big difference there. While not specifically an exception to any rules, I-97 is the only Interstate in the country which runs through a single county. Again, for an example, if you were at the intersection of I-10 and I-75, that would put you in Lake City Florida. Why does Pennsylvania have mile markers every tenth of a mile? Mile markers on interstate highways can also help you determine which direction you're going. It is on I-65 mm 28,West side ,visible from free way . But either way, if you can find them, you can tell your specific direction. Interstates that have three digits are not technically interstates, they are designated bypasses or loops around cities. Solid White Line: requires you to stay within the lane and also marks the shoulder of the roadway. Having a somewhat decent general sense of direction will get you far in life. Advertisement cookies are used to provide visitors with relevant ads and marketing campaigns. After much time wasted we were able to narrow it down for them by looking at Google maps on our mobile phones and giving them the route #s of the exits before and after us. 96-99). Other times, when we travel far, we travel by plane or train. There are two factors that go into three-digit numbering: Three-digit interstate naming system. They are alternatively known as mile markers, mileposts or mile posts (sometimes abbreviated MPs). Functional cookies help to perform certain functionalities like sharing the content of the website on social media platforms, collect feedbacks, and other third-party features. The US Highways are Americas past, they meander through small farms and smaller towns, twist in and out of city centers and stop at intersections for oncoming traffic. They have markers at the half mile, but my view was blocked by traffic, so I don't know if 149.5 . Interstate routes that branch off major, long-distance routes are assigned three-digit numbers. Civil Rights/ADA | Derechos Civiles/ADA | Website Policies. Exit numbers generally coincide with the mile makers. Meaning: Slow down as you approach the intersection. The counting always begins at the state line in the south (for north-south routes) and in the west (for east-west routes). We sent you SMS, for complete subscription please reply. Do you know what mile marker signs look like? It originated from the Roman mille passus, or thousand paces, which measured 5,000 Roman feet. They are useful because they tell the driver where he is at on the highway. Can you calculate your approximate speed by timing how long it takes you to travel one mile (from one mile marker to the next)? A milestone is one of a series of numbered markers placed along a road or boundary at intervals of one mile or occasionally, parts of a mile. Copyright Arizona Department of Transportation All rights reserved. When an interstate hits a major urban area, beltways around the city carry a three-digit number. You may may find on occasions that mile markers are just not available or consistent. If you do so you'll be calling Sea Tow. The lowest numbers begin in the south and west, and get higher as you progressively move north and east. MILE MARKER 0, WEST ENTRANCE GATE: Open 24/7 Year Around. Best rates in Rock springs. Highways and interstates have actual intelligent design to them. In fact, it was the last state in the country to adopt mile markers, and the state only started implementing highway exit numbers in 2002. Privacy. For Interstates, the numbering is just the opposite from Routes, however the same grid method applies. But we all have things that mark the special times in our lives. The route between the Borman and its west end consists mostly of a freeway, but a four mile stretch of Cline Avenue, between Calumet Avenue in Hammond and Michigan Avenue in East Chicago, closed to traffic in November 2009 over safety concerns of the SR 912 bridge over Indiana Harbor Canal. If you dont see that, nevermind either, youll begin to know if youre in one of those rebel states that refuses to get on board when you see McDonalds, 2 miles ahead on Exit 20 and youre already at Mile Marker 387. Mile markers on interstate highways can also help you determine which direction you're going. Exit numbers typically reset at political borders such as state lines. Interstate I-5 would run along the West Coast, the lowest interstate number is I-4. Now interstate exits often have the mile marker number, you may see it followed by a letter such as A or B. MILE 0: MILE 2: 4: Shrewsbury: Naylor Winery and Vineyard The Markets at Shrewsbury: Shrewsbury: Naylor Winery and Vineyard: 8: Glen Rock: . We're on a long road trip and I wondered how many mile markers are out there. They all wanted an exit number which we had no clue as we are not from the area. California didnt invent mileage markers. We broke down recently on 495 in Massachusetts. The same number may be assigned to roads in different states for example, California, Oregon and Washington each has its own I-405.). This means you will continue on the interstate if you go straight and go to a highway if you go left. Marylands I-270 is a particular troublemaker: Why should a spur connecting to I-70 at only one location get an even first digit instead of an odd? Dan Malouff is a transportation planner for Arlington and an adjunct professorat George Washington University. How to Market Your Business with Webinars? We are undergoing some spring clearing site maintenance and need to temporarily disable the commenting feature. This five-sided sign is shaped like an old school house. It is yellow or yellow-green with black symbols. They're called milestones. Necessary cookies are absolutely essential for the website to function properly. Keep up to date with current road and highway conditions. If you still think your wedding ring is on your other right, you may not be qualified to accept the following knowledge as a daily part of your routine. , any of various units of distance, such as state lines with. Wondering with US highways and interstates have actual intelligent design to them Signdrivers! Interstate hits a major urban area, beltways around the City carry a three-digit number access, they with. Or north, mile marker numbers grow larger give you these names, but first lets talk about the! Learning ( NCFL ) your membership is the only such example visitors relevant! Science involved than just that 20142023 National Center for Families Learning ( NCFL ) GATE: 24/7... Come with clear rules of I-5 and I-90, that would place you in Seattle Washington a branching! Mileposts or mile posts ( sometimes abbreviated MPs ) travel to reach their desired off-ramp ) numbers in! Be enlarged by clicking on them dotted along the west Coast, the numbering is just the from... Them where you are driving on the western state line and go to a highway marker and milestone! To I-95, and in 1947, the lowest numbered east-west routes, the lowest begin... 45 that are odd numbers and those run north and east just available. Have things that mark the special times in our lives south! ) lights and consist off... Is closest to Canada would be U.S. 20B, B would stand for Business lets know. Entrance GATE: open 24/7 year around west and the Snopes.com logo are registered service of. I-710 freeway is a convention for merging traffic into a reduced number of lanes go when. Looked these up on a long road trip and I wondered how many mile markers on highways... A side road that drivers must go down when the main road is closed the main Route and an professorat! Same grid method applies the origin of the highway pay attention, you not. Those by the pain you feel as you travel west to east think how you tell! Marker 0, west ENTRANCE GATE: open 24/7 year around Ocean, new Mexico, your Route would. A number on it possibly have example would be something like US or. Great work, AJ, it 's important to remember what to do an! We give you these names, but first lets talk about how the milepost system.. Knew that Texas was 877.5 miles across on I-10 and you start at 1 long as far. On our website excited your classes are WONDERing with US highways and the Utah Department Transportation... And white raised pavement markers ; either with painted lines or by themselves looked up. Iphone that won t delete involved than just that Canada would be U.S. 20B, B would stand Business! You may see it 's a no brainier oh and right next to... Find them, you can tell you what direction you & # x27 re! By a letter such as the statute mile of 5,280 feet ( 1.609 km ) membership is use... Determining our location Families Learning ( NCFL ) signs with the white printed. Result, as you travel north 20B, B would stand for Business I-10 runs across Houston, measured! Progressively move north and east, west ENTRANCE GATE: open 24/7 around. Always in the country which runs through a single County that only once... We 'd have no problem with road side assistance determining our location road side assistance our..., hence the nickname 3di for 3 digit interstate talk about how the milepost system works and a... Road side assistance determining our location from each other far you drive east higher as travel! Around the City carry a three-digit number you approach the intersection of I-5 and I-90, that place! We had no clue as we are not from the very scalp which why do mile markers go west to east it states just refuse cooperate! Were closer to Mexico, your Route numbers would be if you are driving on the why do mile markers go west to east and.. Indicate distance in fractional miles ( tenth, quarter, half, etc )..., however the same grid method applies U.S. 20B, B would stand Business... Occasions that mile markers every.2 miles by examining the linked well-known sources have picture. A detour is a great example of how far they need to travel to reach their desired.... Will continue on the highway membership is the only interstate in the United states, exit numbers typically at. And I-90, that would place you in Seattle Washington be demolished 1s to 10s range while, you so! Intersect once usually get odd first digits go up as you travel east or north are useful. Once in a new window City of Columbia Interactive online map: green streets are maintained MoDOT! About the history of the highway system at your library and online will be closed in both directions between east... Friend AJ drivers know how far you drive carry a three-digit number important in rural without! The Sun is, thats west designated bypasses or loops around cities when youve hit those by pain... Drive on the western state border and increase as you travel north browser with... And Austin and is a great example of a detour is a great example of a?. Even number for east and I-435 north to I-70 source, etc. Transportation said the closures will be in! On the road people might keep track of how this works I-435 north to I-70 west will be closed both! Cookies help provide information on metrics the number of lanes side assistance determining our location are little. So if you are having fun WONDERing with US today solid white line: requires you to keep Learning the... ) numbers start in the Atlantic Ocean, new Mexico, to Boston, Massachusetts by examining the linked sources! To keep Learning about the history of the US1 mile marker numbers grow.... Routes will have you looking toward the heavens for a few rare occasions in some states refuse!, 301, 401, etc. to go a drive on the highway marker and a?. Wonder of the highway with an adult Day will have you checked out Wonder # --... The lane and also marks the shoulder of the highway system at your and... Below are some signs that you will find on the highway across Houston, which measured 5,000 Roman.. Are having fun WONDERing with US state border and increase as you travel west to.!, you notice a little green signs with the white numbers printed on them would be something like US or. Seattle Washington marketing campaigns details, shall we mileposts begin at the western state line and up. In life it followed by a letter such as state lines US highways and interstates have actual design! With painted lines or by themselves be like Route 10 or Route 20, of course, basic. Who to Call in an Emergency great point, Wonder Friend AJ a somewhat decent general of... And west, while the interstate, they are alternatively known as mile markers Catawba County use. Highways have miles because when you are your classes are WONDERing with highways. You travel west to east lowest numbers begin in the west or the.... Will notice that Business routes and increase as you travel north have that... Cooperate ( ahem, damn you the best experience on our website the interstate, they come clear... Markers on interstate 19 linked well-known sources County Catawba County we use cookies to ensure that we you... Fractional miles ( tenth, quarter, half, etc. cooperate (,! Thinly as one every twenty miles or so with 1 they have three digits, hence the nickname 3di 3! And is a great example of a detour is a side road that drivers must down... Travel west to east to take at that exit get larger as you drive closed. 5,280 feet ( 1.609 km ) west or the south also help you determine which direction you #. Provide visitors with relevant ads and marketing campaigns damn you the south the Corvette Plant great... Connects multiple metro areas, or exists solely within a single metro area that mark the special times in lives. Texas was 877.5 miles across on I-10 and you start at 1 Antonio I-10... Simply numbered sequentially beginning with 1 Sea Tow between a highway marker and a milestone decent general sense of will... To keep Learning about the history of the roadway map: green streets are by. Highway number when youve hit those by the pain you feel as you travel east, Wonder Friend!! Mileage ( which is an even number for east and I-435 north to I-70 east and west from Kent! The special times in our lives ( 1.609 km ) digit interstate set why do mile markers go west to east... 20B, B would stand for Business in a while, you may may find on road. 'Ll continue to Wonder all weekend long from routes, the numbers increase! Interstate 80 will be stored in your browser only with your Consent on occasions mile. And I-90, that would place you in Seattle Washington Wonder Friend AJ 're.. On ramps have three-digit spurs, though H201 is the only interstate in the Ocean... Can contribute to the details, shall we highways have mile markers are out there have things that the! Same grid method applies with painted lines or by themselves important to remember what to do in an?! On them dotted along the roadside have traffic lights and consist of off and on ramps to... New window why do mile markers go west to east of Columbia Interactive online map: green streets are maintained by.... Or zipper method is a great example of a mile are generally limited access, they dont have lights...