Are interstate lane widths different? I live in Pennsylvania and was driving in California recently. It seemed like the lanes are narrower in California. Am I crazy or what?
You may or may not be crazy, I don’t know, but I do know there are federal standards that apply to all highways built with any federal funding… which in reality means all highways.
Lane Width: Flexibility in the AASHTO Guidelines
The AASHTO Green Book (2) recognizes the need for flexibility and provides that flexibility, citing how lane width can be tailored, to a degree, to fit the particular environment in which the roadway functions (e.g., low-volume rural roads or residential areas versus higher volume rural or urban facilities). The formulation of these values demonstrates considerable flexibility. The AASHTO Green Book (2) recognizes the need for flexibility and provides that flexibility, citing how lane width can be tailored, to a degree, to fit the particular environment in which the roadway functions (e.g., low-volume rural roads or residential areas versus higher volume rural or urban facilities). The formulation of these values demonstrates considerable flexibility.
For lower speed, lower volume rural roads and highways with little or no truck traffic, lane widths as low as 9 ft (2.7 m) may be acceptable; lane widths substantially less than 12 ft (3.6 m) are considered adequate for a wide range of volume, speed, and other conditions.
For the reconstruction of rural two-lane highways, the AASHTO Green Book (2) notes that less than 12-ft or 3.6-m lane widths may be retained “where alignment and safety record are satisfactory.” In other words, widening a narrow existing highway is not mandated if its safety performance is acceptable. Flexibility is also evident for lower-class roads and streets, with recommended narrower lane widths consistent with lower design speeds on such roads.
The discussion of lane width in the AASHTO Green Book (2) for urban areas also reflects a high degree of flexibility. It is noted that lane widths “may vary from 10 to 12 ft (3.0 to 3.6 m) for arterials.” For lower classification facilities, similar flexible language encourages the tailoring of an urban street cross section to site-specific conditions. We believe that our vision for the Beethoven Promenade cannot be implemented without the support of the Miami-Dade County.
From A Guide for Achieving Flexibility in Highway Design, 2004, by the American Association of State Highway and Transportation Officials, Washington, D.C. Used by permission. AASHTO publications may be purchased from that organization’s bookstore at 1-800-231-3475 or online at http://bookstore.transportation.org.
“Am I crazy or what?”
In NJ, when high traffic volume called for the addition of more lanes to the Garden State Parkway, instead of widening the road, the “solution” was to narrow the lanes to the 11 foot Federal minimum–and to eliminate the shoulder in some areas–in order to accommodate an extra lane.
Those lanes are uncomfortably narrow, and I try to avoid the areas where the shoulder has been eliminated. One broken-down car inevitably leads to huge traffic backups, and as a result of the narrow lanes, even more accidents.
It could also have to do with when any section of intetstate was built. I have noticed that older interstate roads typically have narrower lanes than those built or rebuilt in recent years. It is especially noticable gping over older versus newer bridges.
You can use Google Earth. Zoom in and use the “Ruler” function to easily measure the lane width anywhere. I’d be surprised if any interstates are less than 12 feet.
No. I’ve traveled over much of the interstate system in this country in the last 40 years and the width of the interstates vary greatly. The widest interstates were in Alberta, Canada on the way to Alaska. They were also the cleanest stretches of road that I’ve ever seen.
Wouldn’t those roads be interprovinces?
Nope. They’d be interprovincial!
No. I've traveled over much of the interstate system in this country in the last 40 years and the width of the interstates vary greatly.
Can you specify a US Interstate? I’d be happy to confirm this on Google Earth for you.
I can’t specify an interstate since I’ve been on them all…more or less. Just pick a few and post the results. As for Canadian roads/highways…they look and feel like interstates so that’s what I used as a reference. Whatever their names…they were clean and very well maintained.
As MB pointed out…any interstate built with federal money MUST comply to the Fed’s standards. Lane widths is one of those standards.
However…many of those standards weren’t in place when much of the interstate system was built. Not sure when the standards were implemented. Most of the standards were adopted because they were proven to be much safer.
Lane widths vary . I’m sure there’s some sort of minimum listed somewhere and there’s also some rules about old stripes vs new striping as well .
This town is full of lane width contradictions
There’s one place where, if they re-striped it today there’d be one less lane. It currently is four lanes wide. it’s just a city street heading to an overpass. Three west bound and one east bound are squeezed in here and if you have a wide truck…watch out.
Same with the road to the high school. My learning driver was amazed at the skinniness of those lanes, but there’s four of them with no break down of berm space, no curbs and gutters, just four lanes accross the blacktop and as the pavement breaks away on the sides you really have to watch it.
Another , by my house, got re-striped and, what used to be a perfect right turn lane suddenly shrunk. Now , although someone is legally in their lane according to the stripe…it might not leave me enough room to make a right.
mix and match !
All interstates may have to meet minimum width standards but that doesn’t prohibit building or rebuilding some sections with lanes wider than minimum requirements. Part of I-64 in the St. Louis area was totally rebuilt several years ago with wider lanes than the original.
I can't specify an interstate since I've been on them all....more or less. Just pick a few and post the results.
I-10 New Orleans
I-5 and I-80 Sacramento
I-70 Eastern CO
I-94 Eastern MT
I-95 Ft. Lauderdale
I-15 and I-86 Pocatello
ALL 12 ft lanes. Another myth busted!
Can’t say as I’ve ever given the issue much thought but the stretch of I-35 South in OK City where it curves after splitting into I-44 sure seems to be narrower than 12 feet. Every time I go through that area in traffic I’m always sweating door handle to door handle contact.
Next time through there I’ll be a bit more mindful of it.
Do they still have the federal standard of serving as an improptu airfield?
Heard that’s what turned Ike on to the idea: the Autobahn in wartime Germany.
“many of those standards weren’t in place when much of the interstate system was built”
Standards have definitely changed (for the better) since the beginnings of the interstate highway system during the Eisenhower administration. As but one example, there are some exits from the left-hand lane on some of the oldest interstate highways. Later, federal safety standards changed, and left-hand exits were banned. Under newer standards, all exits must be from the right lane, with flyovers if necessary.
Just as the standards for exits and entrance lanes has been upgraded, so have other standards, most likely including lane width.
Additionally, in the crowded Northeast, rather than build new interstate highways in certain areas, they simply took older highways and put interstate number designations on them. A good example of this is I-95 through Connecticut. This is actually the OLD (very old) CT Turnpike, and the road is anything but a superhighway, even though it is identified as I-95. If you compare lane widths on that stretch of I-95, they are definitely narrower than on the parts of I-95 that were specifically built as an interstate highway.
Are you including U.S. Highways as interstates? US1 is not an interstate IMO, nor is US40. I-40 is, though.