Not sure if this belongs in International, but what's the longest continuous dual carriageway route anywhere in the world? I woud guess it would be in the US? Or woud it be in Europe?

Are you looking for the longest uninterrupted central reservation or for a signed road number with two carriageways?

Well I was thinking more on the lines of the former, but the latter sounds interesting too.

Just off the top of my head and as an opening gambit: I-95 which runs down the entire eastern seaboard of the USA and is I believe 1,894.04 miles in total.

However, this is bound to be wrong and just doing some basic research, is there a gap in New Jersey? However, even if the number isn't continuous, the dual carriageway surely is.

Failing this and if different route numbers can be used, you must be able to get a DC route from the furthest South West USA to North East USA or from Homestead, Florida (South East) to Vancouver, Canada say and even if you can't (because a border crossing won't count) to somewhere else in NW USA.

Stockholm is a very, very, long way from here by motorway, and probably even longer from somewhere like Lisbon....

I would say I-90 in the USA. over 3000 miles in length and dual carriageway the entire length, I have travelled about 1,050 miles of it. The only caveat might be the Chicago Skyway that was donwngraded from Interstate standard and is now signed "To 90", although when the Skyway works finish this will apparently change and it will become I-90 once again.

I think that just about pips it.... at the moment the longest in europe I can make is Gälve in Sweden to Cartagena in Spain, at 2.500 miles (at the moment), so I-90 probably wins (and it's nice and continuous numbering....)

Having said that, the Swedes are extending the E-04 motorway section north, and the Spanish are building motorways everywhere.... so maybe soon we'll be able to do better.

Then again, the Danes are sabotaging the efforts by planning to build more bridges to cut the corners off!

<Homer>
Mmmmm......Interstate-90......
</Homer>

Interstate Guide
Wiki

The only fly in the ointment (perhaps) is found here:
"You can't be the longest Interstate without having a few quirks. In Montana right by the ID border, I-90 is not a divided highway for a few stretches. The speed limit there is still "Reasonable and Prudent""

Though Wiki and Interstate Guide don't mention this!

in terms of longest journey, from the end of route 20 in Quebec to wherever highway 1D ends in Baja California must be rather long. the shortest fully-freeway route goes via Montreal, Toronto, I-69, Indianapolis, I-70, St Louis, I-44, I-40, I-15, I-805 then over the border. It could be that the top end of I-95, rather than entering Canada, is further away from the end of freeway in Mexico.

A route using the other diagonal, from Homestead, FL to Vancover (unfortunately the freeway to Kamloops doesn't link up with the US network) might be longer, using the FL turnpike, I-75, I-24, I-57, I-64, St Louis, I-70, Denver, I-25, I-84, I-82, I-90, I-5 approx shortest freeway route.

Is Stockholm further from Lisbon/southern Spain than Moscow?

I'm fairly sure you can get to Warsaw by dual carriageway from the Atlantic, and that Minsk-Moscow is dual, but I'm not sure about Warsaw-Minsk.

Pacific Highway I think is dualled all the way from Canada somewhere, maybe even Alaska to Panama. Thats a fair distance. Must be 4,000 miles at least.

Is it the M10? *puts hand up*

Isn't there a gap in the I-95 as it hijacks the Washington Beltway?

I think you could be right and I mentioned a possible gap elsewhere when I suggested it. For more information there is a whole forum devoted to the road here.

Here:
Gaps in Interstate Highways

This information doesn't seem to be correct. If you look here, you can see I-90 does have a very narrow grassy median. In mountainous sections, such as near Missoula, this median gives way to a Jersey barrier. The statement about "reasonable and prudent" has not been correct since (I think) 1998 or 1999, when the Montana legislature approved a 75 M.P.H. speed limit on Interstates.



No. That gap has not existed since plans to route I-95 through D.C. were abandoned. Existing I-95 inside the Beltway then became I-395 while I-95 was routed over the southern arm of the Beltway. That length has been signed as I-95/I-495 for almost twenty years.

If you're referring to the Pan American Highway, then the section of it linking Alaska to Canada - the Alaska Highway - is most definately not dualled. My 2002 USA map still shows a couple of sections as unpaved.

The most northerly dualled section of the Pan-Am Highway is probably somewhere around Edmonton, but I don't think the dualled section extends from there south to the USA. The first dualled section is probably I-15 in Montana. You could travel to Mexico on dualled roads, but since I haven't got the map to hand, I don't know how far one could travel into Mexico on them.

Andy

Is it concievable that the Pan-American highway will ever be dualled all the way from Alaska to Chile? I know, first hand, that there are some very long, but not yet continuous, grade separated sections in Chile.

What about the darien(sp) gap

But this length has confirmation signs with both I-95 and I-495, so it's still I-95. The US double-sign all their multiplexes.

The east-west routes must be longer though -- I-10 from Santa Monica, CA to Jacksonville, FL; or I-80 from San Francisco, CA to New York, NY; or I-90 from Seattle, WA to Boston, MA (I think that's where it goes).