SultanOfSwing

Not quite, but close. There are a set of rules governing the numbering of auxiliary highways such that any 3 digit highway is associated with a 'main' interstate using the system XNN (where X is a number denoting a spur or a bypassm with odd numbers denoting spurs and even denoting bypasses/loops, and NN is the number of the main interstate, single digit highways being prefixed by a '0').

So in your example above, I-405 is a bypass of LA (denoted by the even '4') and connects to and from I-5 (denoted by the '05'). However, highway 522, if it were an interstate, would be a spur of I-22 except that there is no I-522.

Juniorjay12

Congestion is nothing when you're used to driving in London at any point of the day lol.

SultanOfSwing

I-94 around O'Hare at about 5pm is particularly fun. Wait, did I say fun? I meant soul-destroying.

mrken30

So true, in London it used to take me 90 mins to do 13 miles, here it takes 90 mins to do 19 miles. So definitely less congested, but still not good.

In Milton Keynes , it took 20 mins to do 12 miles.
I think Reading was worse than London. almost an hour to do 3 miles

I don't have the American attitude of feeling good sitting in traffic.

Bob

Is this a midwest thing? It isn't like that over here.

SultanOfSwing

No, it's an interstate thing. General rule is if an auxiliary highway connects to the main highway once, it's a spur and gets an odd leading number. If it connects in two or more places (loops and bypasses), it gets an even leading number. Sometimes bypasses only connect in one place, but they still get the even leading number as far as I know.

Pulaski

Yes it is. You have three main interstates running through your end of MA: 90, which is east-west, and 93 & 95, which are north- south.

Then you have 495, which is a bypass, 395, which branches off 95 in CT, 295 which is a bypass in RI, and 290 which is a branch off 90, plus 190 which is a branch off 290.

With the possible exception* of 290, all those numbers conform to the rules which SoS summarized above.

* I believe that deviations from the numbering convention occur when roads are not completed as planned, so I suspect that originally it was intended for 290 to come further east and reconnect with 90 fairly close to downtown Boston.

When I moved to NC, Charlotte had an orphan piece of interstate that was only a spur off 77, but was numbered 485. It had been there, I believe since the mid 1990's, but it wasn't until the late 00's that it finally connected to 85, when it should have been a "1", and a couple of years later before it connected to a second point on 85, which per the numbering convention would have qualified it as a "2". It was only a couple of years ago that the entire loop was completed, thereby meeting the qualifications for being a "4".

SultanOfSwing

Unrelated to Bob's post but an interesting thing about the 3 digit highway system is that because they are all contained within one state, it allows for duplication of numbers without confusion.

We also have an I-190 (spur of I-90 into O'Hare) and an I-290, which bypasses the main line of I-90 in downtown Chicago (and does connect to I-90 itself twice as well).

Though, for I-94's auxiliaries, between Michican, Illinois, Wisconsin and Minnesota, all possible numbers except for 594 and 994 have been used and each state uses unique numbers, presumably due to their proximity to each other on the main line.

mrken30

I-205 that bypasses Portland, keeps the same number both in Oregon and Washington.

SultanOfSwing

That one's right on the state line, so it wouldn't cause confusion.

mrken30

You would be surprised, some people are easily confused around here.

SultanOfSwing

That does not appear to be Oregon and Washington DOT's problem

dj6372

My 35 miles journey took exactly 2 hours today, part of the journey was a 3 lane down to 1 lane while they trimmed the trees!! Yes at rush hour between 8am and 9am they closed 2 effin lanes, and I thought the councils in UK were retarded!!!!

Jerseygirl

That's where NJ usually excelled. Construction on major roads normally took place during the night and between 9 am and 3 pm during the day. During rush hours they tried to put the road back to as near normal as possible. The work was also completed fairly quickly. When a fuel tanker overturned on I80 the heat from the fire badly damaged a major overpass and it had to be rebuilt. That was late Thursday...by Monday morning I80 was as good as new again.

chawkins99

Apart from the occasional knob-head decision (Christie-gate), the US are much better at road work than the UK.

When we lived in Alabama, they re-surfaced a 20-mile stretch of I-65 and I never saw a single worker. It was all done at night. Each day, there would be a couple more miles of fresh black-top.

Sorry for the hint of politics in there.
In contrast, on a visit to the UK a few years ago, we needed to visit the US embassy for visa stamps. It took us 6 hours to get back to Birmingham, largely due to about 30 miles of contraflow on the M1. Not just cones. Solid steel barriers that must have taken weeks to construct before they even started on the actual repair work.