Why do divided Russian highways have an abundance of U-turns in the central reservation?

[AnOrdinarySABREUser]

Example

I understand that a majority of divided Russian highways were built during the Soviet era, and so were subject to different standards expected than today. Still, it strikes me as odd that Russian and/or Soviet designers decided to add so many U-turns here, especially given the extra risk introduced by gaps in the central reservation. Perhaps there was a need for these given the vast distances the highways have to cover in order to link Russian cities together?

[WHBM]

A number of such Russian roads are on-line upgrades of existing roads (all done in more recent times, they are not Soviet), given there is commonly little or no frontage development on these in the country. There are though a series of existing side roads from these, and it's just a different design standard that rather than build bridges and on/off ramps, they just do a LILO (actually a RIRO of course), and periodically provide this facility for joining/leaving traffic to turn onto the opposite carriageway. Proper new build Russian motorways don't have them.

Unlike Western Europe, or particularly North America, there is little or no tradition of doing the "vast distances" by car, which along with most trucks are used generally for local work. Inter-city travel is still very much the province of rail and air; it's still unusual to drive between Moscow and St Petersburg, the two principal cities, same distance as London to Aberdeen. Winter (and spring) travel through the Russian endless forest is a notable challenge - something that both Napoleon and Hitler would attest to.

[Octaviadriver]

The A1 in Lithuania between Kaunas and Klaipėda had several U turns at junctions that weren't built as grade separated, but all have been closed and mostly grade separated except this one:
https://goo.gl/maps/SXnQdqDky9oMGKS18
When you approach this junction, the speed limit drops from 130kph to 110 kph and it is not a motorway for this short stretch.

This motorway was built when Lithuania was still part of the Soviet Union.
https://goo.gl/maps/LNjPLAifnt253yBGA

[roadtester]

Wikipedia has some quite good information on interesting examples of analogous at-gradery on the US Interstate network.

https://en.wikipedia.org/wiki/List_of_g ... ersections

[WHBM]

This motorway was built when Lithuania was still part of the Soviet Union.
https://goo.gl/maps/LNjPLAifnt253yBGA

There were a very few "improved roads" built in Soviet times, of which the main route westwards from Moscow past Minsk in Belarus to Brest at the Polish border was the key one - but it's just a dual carriageway, with at-grade signalled junctions. https://www.google.com/maps/@54.7296932 ... ?entry=ttu

Moscow to Leningrad (nowadays St Petersburg) had long stretches of just S2 carriageway (with shoulders), although as common on radial routes out of main cities having dual carriageways for a good initial length out, thereafter with scattered frontages directly onto the carriageway, including, though now bypassed, Tchaikovsky's house at Klin (now a museum). The entrance to that is a RIRO with nearby U-turns as well ! https://www.google.com/maps/@56.3277675 ... ?entry=ttu

[bothar]

I travelled from Riga to Vilnius about 15 years ago and I recall this U turn format. Basically, Lilos but the opportunity to U turn relatively soon.

Of course, in Kaliningrad the Russians demolished the bridges on the Berlinka Autobahn and used the materiel as fill, although that route was perhaps not going to be important in the new dispensation, it could have been used to reach the DDR.

[WHBM]

Here's one in the USA, not done nearly as well as the Russian ones, for example no deceleration lane for left turners off the freeway. And Texas is an 80mph freeway speed limit state

https://www.google.com/maps/@31.212243, ... ?entry=ttu

[roadtester]

Here's one in the USA, not done nearly as well as the Russian ones, for example no deceleration lane for left turners off the freeway. And Texas is an 80mph freeway speed limit state

https://www.google.com/maps/@31.212243, ... ?entry=ttu

I think that must be one of the I10 ones in the Wikipedia article I linked to above.

[RichardA626]

They are common in some parts of Turkey to access properties on the opposite carriageway without having to drive to the next major junction.

[AnOrdinarySABREUser]

Interesting stuff, guys! I wonder if this design could be used as an alternative to standard crossroads or T-junctions on at-grade dual carriageways back at home, more specifically the Russian variety as opposed to some of the other examples listed on here, such as the unfortunate American example.

[orudge]

It was not uncommon on the highways I travelled in Brazil to see minor roads connected with a T-junction (no central reservation gap), then a “retorno” shortly after, comprising a deceleration lane in the centre of the road, then a decent sized U-turn facility, possibly with an acceleration lane too. There’d then be another “retorno” on the opposite carriageway to provide access for traffic leaving the highway onto the minor road.

There’s something a little similar here on the A90 - traffic for Bonnyton is signposted to do a U-turn then turn left, and the same for traffic wanting to head north from the side road.

[freebrickproductions]

There’s something a little similar here on the A90 - traffic for Bonnyton is signposted to do a U-turn then turn left, and the same for traffic wanting to head north from the side road.

We have similar to that here in the US, often called a "Michigan Left" due to the fact that Michigan started building a lot of them on their roads by the 1960s. Here's one such example here in Alabama, down on US 280 near Birmingham.

There's also a similar variation, which I've seen referred to as a "Superstreet" before, which ALDOT has also used at some rural intersections on divided highways, here's one such example here in Madison County on US 72 out in Ryland.

[Octaviadriver]

There were a very few "improved roads" built in Soviet times, of which the main route westwards from Moscow past Minsk in Belarus to Brest at the Polish border was the key one - but it's just a dual carriageway, with at-grade signalled junctions. https://www.google.com/maps/@54.7296932 ... ?entry=ttu

I drove to Belarus in 2012, though I didn't go along the route mentioned above, but I did drive along the M6 motorway from Lida to Grodno. When I went along it, it was 2 lanes with no centre crash barrier and with at-grade junctions with bus stops and pedestrian crossings.

They were changing a junction to grade separated.

We had to share the other carriageway where ours was closed for the repairs. There were no cones, barriers etc to separate the two opposing flows of traffic.

Sorry that the photos are of low quality.

[WHBM]

When I went along it, it was 2 lanes with no centre crash barrier and with at-grade junctions with bus stops and pedestrian crossings.

A38 near Taunton ?

https://www.google.com/maps/@51.0447117 ... ?entry=ttu

[Vierwielen]

Example

I understand that a majority of divided Russian highways were built during the Soviet era, and so were subject to different standards expected than today. Still, it strikes me as odd that Russian and/or Soviet designers decided to add so many U-turns here, especially given the extra risk introduced by gaps in the central reservation. Perhaps there was a need for these given the vast distances the highways have to cover in order to link Russian cities together?

I drove along the motorway in my Google Car and could not see any evidence of the U-turns.

[AnOrdinarySABREUser]

Example

I understand that a majority of divided Russian highways were built during the Soviet era, and so were subject to different standards expected than today. Still, it strikes me as odd that Russian and/or Soviet designers decided to add so many U-turns here, especially given the extra risk introduced by gaps in the central reservation. Perhaps there was a need for these given the vast distances the highways have to cover in order to link Russian cities together?

I drove along the motorway in my Google Car and could not see any evidence of the U-turns.

Satellite imagery and the map layout suggests otherwise. You can see other examples further up the thread as well posted by others.

[MotorwayGuy]

We tend to always take safety more seriously than efficiency, which although isn't a bad thing is why we end up with bypasses with 10 roundabouts on them. That's not always the case in other countries, especially in ex-soviet countries where the cheapest and/or most efficient option is often chosen. Even in the United States uncontrolled flat junctions and u-turns are common, such as these on Highway 12 in Michigan, which allow traffic from side turnings to cross the median.

[Chris Bertram]

We tend to always take safety more seriously than efficiency, which although isn't a bad thing is why we end up with bypasses with 10 roundabouts on them. That's not always the case in other countries, especially in ex-soviet countries where the cheapest and/or most efficient option is often chosen. Even in the United States uncontrolled flat junctions and u-turns are common, such as these on Highway 12 in Michigan, which allow traffic from side turnings to cross the median.

Doesn't that have a lot to do with them being intended as "development" routes rather than pure by-passes?

[KeithW]

We tend to always take safety more seriously than efficiency, which although isn't a bad thing is why we end up with bypasses with 10 roundabouts on them. That's not always the case in other countries, especially in ex-soviet countries where the cheapest and/or most efficient option is often chosen. Even in the United States uncontrolled flat junctions and u-turns are common, such as these on Highway 12 in Michigan, which allow traffic from side turnings to cross the median.

Doesn't that have a lot to do with them being intended as "development" routes rather than pure by-passes?

Its pretty common in Canada, you have much lower traffic volumes and outside the big cities lower population density. Here is the Yellowhead Highway.
https://www.google.co.uk/maps/@53.57584 ... ?entry=ttu

The Trans-Canada Highway
https://www.google.com/maps/@51.258923, ... ?entry=ttu

If you are delivering or collecting from some business in the sticks they do what we did on A roads - leave a gap, heck we still have that now on the A1.
https://www.google.com/maps/@52.1217631 ... &entry=ttu

[WhiteBlueRed]

It's a common solution here, mainly due to it's low cost, to reduce conflicts (and thereby improve safety) when the side road is low-trafficked.
Speaking of that, a road between my city and a nearby village is being widened from S2 to D2 (around which there are plenty of dacha communities, demand to and from which is high during the summer months). That project includes replacing a traffic light junction (they were installed in 2013 only for safety reasons) mid-way along the road with a RIRO, and subsequent U-turns down the road. The T-junction at the end of the road will also become a RIRO with U-turns down the road.