Why are the "Loops" not Interstate (Phoenix, Tucson: area, distance)

[phx1205]

Originally Posted by adriver

interstates are multi state. its a phoenix metro loop.

/thread.

Easy there. Where does I-17 go, for example.

[new2colo]

Originally Posted by Hschlick84

Wouldn't loop 303 be considered a parkway/bypass since it doesn't go in a loop? I'm sure if it were designated by the feds, it would be called I-210 or something. Loop 202 would be I-410 or I-417.

In Arizona, parkways are different than freeways. Parkways in Arizona still have intersecting streets, limited access control, and can still have traffic lights. All the loop freeways here can be considered bypasses. Before the construction of the 303, someone traveling from Flagstaff to San Diego would have probably used the 101 to bypass going through Phoenix, while someone traveling from Globe to Prescott would probably use the 202 and the 101 in the same manner. In essence, the 101, 202, and 303 can all be considered beltways. However, due to geographical and political constraints, none of the freeways will completely encircle the Phoenix area.

[cjseliga]

Originally Posted by new2colo

In essence, the 101, 202, and 303 can all be considered beltways. However, due to geographical and political constraints, none of the freeways will completely encircle the Phoenix area.

The closest thing Phoenix could have that would be a "true" loop or beltway, would be if you take the entire 101, then add the 202 from Price west to the future South Mountain Freeway to I-10, and even then a part of I-10 would have to be the a part of the beltway.

[cjseliga]

Originally Posted by phx1205

Easy there. Where does I-17 go, for example.

Or I-19 for that matter, or I-2 and I-27 in Texas or I-97 in Maryland, or I-41 and I-43 in Wisconsin, etc., there's actually many examples in the US where an "interstate" is just in one state.

[swbrotha100]

Originally Posted by Hschlick84

Wouldn't loop 303 be considered a parkway/bypass since it doesn't go in a loop? I'm sure if it were designated by the feds, it would be called I-210 or something. Loop 202 would be I-410 or I-417.

Back in 1985, these were some numbers proposed:

I-510/SR 510 -- currently SR 51
SR 417 -- currently Loop 101 from I-10 to I-17 (Agua Fria Fwy)
SR 117 -- currently Loop 101 from I-17 to Loop 202 (Pima Fwy and Price Fwy)
SR 517 -- currently Loop 303
SR 217 -- currently Loop 202 from I-10 Ministack to SR 143

BTW Phoenix is not the only metro area where interstate loops and spurs were planned but not built (or something different was built). For example, in the Denver metro, I-470 was planned, later cancelled. Now there's C-470, the toll road E-470, and the Northwest Tollway which all combined form most of a circle around Denver.

[Pink Jazz]

Here is what would be my Interstate numbers for Phoenix area freeways:

• Loop 101 - I-410 (I-210 I think would be reserved for SR 210 in Tucson if it ever becomes a full freeway)
• Loop 202 - I-610
• Loop 303 - I-217
• US 60 - I-317 (it would be a spur of I-17 that would start from its southern terminus and would go east to Gold Canyon, with the westernmost portion concurrent with I-10)
• SR 51 - I-510
• SR 143 - I-110
• SR 24 - I-710
• SR 30 - I-810
• Pinal North-South Freeway - I-310

[FirebirdCamaro1220]

Originally Posted by adriver

interstates are multi state. its a phoenix metro loop.

/thread.

We are talking about 3 digit interstates, which are local routes, like I-105, I-110, I-210, I-215, I-405, I-605 and I-710 in Greater LA for instance...

[Beardown91737]

Interstates don't have to leave a state, like I-17 and I-19.

Some roads are kept off the Interstate system because the state DOT will have an easier time if they don't have to do compliance with federal rules.

In California, I-210 was built from San Fernando to San Dimas in the early 1980s. Neither end met I-10. In 2002, SR-210 was completed from San Dimas to Fontana. Then in 2007, the gap between SR-210 and SR-30 in San Bernardino was completed. SR-30 was renamed SR-210, and the freeway that Californians call "the 210" linked the 5 in San Fernando with the 10 in Redlands. If it had been in the interstate system, there may have been upgrades required to the former SR-30 section in San Bernardino.

[FirebirdCamaro1220]

Originally Posted by Beardown91737

Interstates don't have to leave a state, like I-17 and I-19.

Some roads are kept off the Interstate system because the state DOT will have an easier time if they don't have to do compliance with federal rules.

In California, I-210 was built from San Fernando to San Dimas in the early 1980s. Neither end met I-10. In 2002, SR-210 was completed from San Dimas to Fontana. Then in 2007, the gap between SR-210 and SR-30 in San Bernardino was completed. SR-30 was renamed SR-210, and the freeway that Californians call "the 210" linked the 5 in San Fernando with the 10 in Redlands. If it had been in the interstate system, there may have been upgrades required to the former SR-30 section in San Bernardino.

What's now CA 210 is supposedly going to be renamed I-210 this year, after some touches are finished at the 210/15 and 210/215 interchanges

[cab591]

Fun related-note, in case anyone was wondering about the numbering system for US interstates:

The map posted by Hschlick84 on page 1 does a decent job explaining it.

Three digit interstates are always going to be side routes off of a major interstate. (I-110, -210, -310, etc). The last two numbers signify the interstate the route is off of (so the numbers I quoted earlier would all be off of the I-10). The first number does tell you useful information as well:

- an odd number (-110, -310, -510) is a spur route. This would start on the designated interstate (I-10, in this example) and end elsewhere. It could terminate (ending in some town), or connect to a differently numbered interstate.

- an even number (-210, -410, -610) is a loop. This will both start and end connecting to the designated interstate.

The numbers can be re-used between states (for example, you could have an I-210 in Phoenix, and an I-210 in Los Angeles, even though they're not the same road), but not within states. Instead, within the state, the leading digit rises in the same direction as the mileage markers (east to west on even numbered interstates, south to north on odd numbered). For example, San Antonio, TX, has I-410, and Houston has I-610.

While Pink Jazz's numbering theory is mostly plausible, this is the one mistake they made -- I-210 would not be reserved for Tucson, because the numbering would go east-west along the I-10, even though it seems like it would make sense to reserve I-210 for SR-210.

EDIT: And on the above note about the I-210 in California: the names are often designated before the route is completed. Changes during construction, or additional interstates / freeways built later, can disrupt the numbering system.