I’ve noticed that some major highways (e.g. Florida Turnpike, Garden State Parkway) lack Interstate numbers. Do they not meet Interstate standards for some reasons? Are there any other highways in the same status?
The Garden State Parkway is not an Interstate, it is a New Jersey Highway built by NJ without Federal Interstate money. It is also maintained by New Jersey, largely through the tolls it collects.
Original construction was a 4 year projects costing 330 million and financed via bonds.
Follow the money - where a freeway/highway is funded determines who gets to slap a number on it.
A highway can also be downgraded from interstate to state route:
There are 2900 miles of toll roads in the Interstate Highway system. Many of them were built and are maintained solely with tolls and predate the Interstates. Example is the PA Turnpike which is I76/276/476 depending on which stretch you are driving. Which toll roads get interstate designation was determined on a case-by-case basis, primarily depending on whether they fit into the network:
One of the controversial issues Congress considered before passing this legislation was what to do with the turnpikes that had been built or planned in Interstate corridors without Federal funding. In an extensive congressional debate, members considered purchasing the bonds to allow removal of the tolls, but this option would have cost hundreds of millions of dollars without creating any new Interstate mileage. Another option was considered—constructing toll-free Interstate highways in these corridors—but it would have diverted funds needed for new highways in areas not served by Interstate-type facilities. It also would have jeopardized the legitimate right of the toll authorities to pay their bondholders. Therefore, Congress decided to include some toll facilities in the Interstate System to ensure connectivity.
Federal law has changed over the years to allow turnpikes on the Interstate System under other circumstances. In all, the 46,876-mile Interstate System includes approximately 2,900 miles of turnpikes.
Back to the OP: There are construction standards that need to be met beyond just being limited access.
The FL Turnpike is the same basic story, plus/minus some details… Not a federally funded highway, so not part of the Federal Interstate Highway system.
Moving back to the OP, the term “interstate” is not synonymous with “highway” or “freeway” or “wide road without traffic lights.”
Federal funding is not a requirement for Interstate designation.
Different roads are funded differently. Off the top of my head, there’s interstates, national highways, state routes, county roads, township roads, and city streets. Usually, their numbers and names are locally unique.
The style of the road is a separate characteristic: number of lanes, limited access or not, lights vs signs vs roundabouts, toll vs free, etc.
True, but once a highway gets an Interstate designation, it becomes eligible for future Federal funding.
The one I don’t understand is, there’s at least one road in Ohio that has a US Route number, and the infrastructure on it appears to be fully at interstate levels. If it’s already part of the federal system, why isn’t it an interstate?
It may not rise to the full level required for an Interstate Highway designation, or there may be other hoops to go through or requirements put upon the state if they wish to be designated. Which highway are you referencing?
This. US 41, from the Wisconsin/Illinois state line, to Green Bay, was re-designated Interstate 41 in 2015; my understanding is that a number of improvements (particularly from Milwaukee to Fond du Lac, and Appleton to Green Bay) were required in order for the highway to meet Interstate standards. In particular, they needed to update some interchanges, and remove grade-level intersections in rural stretches of the road.
There is something quite similar in the UK. We have the Motorways (M1, M6, M5 etc), but then there are other major trunk roads (eg the A55 North Wales Expressway) which do not have an ‘M’ designation.
It probably has to do with some obscure Government regulation?
In the 80s CA-17 was designated as I-880 so it could receive federal funding for maintenance but does not meet interstate standards, mainly clearances. It included the Cypress Street viaduct that collapsed during the Loma Prieta earthquake.
The same thing happened in St. Louis MO while I lived there. I-64 ran from Norfolk VA all the way across several intervening states into Illinois, then across Illinois to the the Mississippi River, then across the river into Missouri where it abruptly became US Highway 40/US-61. Then continued west and eventually northwest into North Central MO.
The US-40/61 part had been built post-depression and into WW-II. In the dense city and inner-ring 19304/1940s suburban environs it was limited access, but narrow with tight turns, short onramps, no acceleration lanes, etc. Once out into the semi-rural exurbs, it was two lanes each way, widely divided, 50ish speed limits, and with grade crossings every couple of miles. But through the intermediate 1970s-2000s suburbs it had been built from the git-go to modern interstate standards.
For about 5 years it was construction hell as they simultaneously upgraded the city part and the exurban part to full interstate standards. At the end of which they triumphantly rechristened that entire 42-mile segment I-64. Yaay!
It stung to live through but the result was better than even the boosters had hoped for.
If I’m not mistaken, a number of “parkways” in the NYC area can’t be made Interstates due to their low bridges from the Moses era to keep trucks off them.
By the way - are there any Interstates that ban or restrict trucks - more than just keeping them out of a passing lane?
Only one section, as far as I know, prohibits trucks, and that happens to be close to where I live. It is on part of I-580 in the San Francisco Bay Area. From that Wikipedia article:
“Trucks over 4.5 short tons (4.1 t; 4.0 long tons) are prohibited through Oakland between Grand Avenue and the San Leandro border. Specifically, eastbound trucks cannot travel beyond Grand Avenue/Lakeshore Avenue (exit 21B), and those going westbound must get off at MacArthur Boulevard/Foothill Boulevard (exit 30)”
There are also stretches of interstate like I-93 traveling through Franconia State Park in NH. It’s a designated interstate but only has 1 lane in each direction and the speed limit is 45 MPH. Apparently that type of roadway is called a Super Two. I believe there are a few sections of Interstate like this; in Franconia Notch it was done to reduce environmental impact during construction.
The US Numbered Highway System is independent of the Interstate Highway System.