By Heather Hogeland & Kim Grimm
We have a truly magnificent Interstate Highway System here in America that connects states to one another almost seamlessly today. It hasn’t always been so, in fact we remember when we began driving big trucks there were a lot of unfinished roads all across the country. It is a very intricate system, like a circulatory system (that’s why they call them arteries) of roads, highways, bridges, and tunnels. There are a few basic tools you may already be using, but if you don’t know them, there’s no time like the present to learn them.
When our Interstate System was developed, the engineers and their counterparts came up with some rules that are still being used to this day. East/West interstates are numbered with even numbers, Southern mostly being smaller numbers working their way bigger as they go North (the idea originally was to avoid conflict with the numbered US Highways already in use, but in reverse). The North/South interstates are numbered with odd numbers, low to high, from West Coast to East Coast. This system makes it simple to locate any interstate, anywhere in the country, on any map at any time. (This is why, in ALMOST every state, mile markers are numbered West to East and North to South as well.)
Once a road is determined to become a part of the Interstate System and the funding for that road is approved, it is assigned a number. That number is based on what type of relationship the new road has to the existing highway. If the new road is going to branch off the existing road and not rejoin it, it’s called a “spur”. If it leaves the main interstate, but will rejoin it at another point further down the road, it’s called a “loop”. A spur will be numbered with an odd number attached to the main interstate number and a loop will be numbered with an even number. This is important to know because if you find yourself in an unfamiliar place, lost and wondering whether or not you’ll be able to get back onto the main interstate from where you are, this knowledge can help you figure it out.
A good example of this is in southern California where I-10 runs East and West through Los Angeles area. Some time ago, the federal government agreed to include the 7, 11, & 210 local freeways in the Interstate System so they changed their designations to the I-710, the I-110 & the I-210. Both the I-710 & the I-110 are spurs, they leave the I-10 and head South but the I-210 leaves I-10 at the base of the grapevine and runs along the foothills all the way to Redlands where it rejoins I-10. If you are on the I-210 and want to get out of town just continue heading East, eventually you will rejoin I-10 on the other side of all the traffic! This is also good information to keep in mind anytime you are in a new location and need to travel off the main highway. Remember, if you are on a spur you’ll probably need to make plans to retrace your steps to get back onto the major interstate when you’re all finished with your load that day. I can’t tell you how many times just knowing this has helped me during my 40 year career!
Another useful tip we can share with you about signs on interstates, is to pay attention to the placement of the exit number, is it on the right side or the left? Depending on the answer, this will tell you which side your exit will be on, right or left side.
We understand that many of you use a GPS these days, heck we do too. But, we thought you might want to know these facts just in case you are in a situation where you need to revert back to using an atlas.
Heather Hogeland and Kim Grimm are CDL holders and longtime friends with a combined 75 years and 7 million miles of driving experience. Both are writers and have a love for everything trucking, as well as, furry, four-legged friends. Kim is currently a full-time owner-operator and part-time writer. Heather writes for various trucking publications and enjoys traveling with her husband Roger.