Cambodia: Development and Its Discontent

[cpzilliacus]

N.Y. Times:  Development and Its Discontent

PHNOM PENH – In 2010, the Cambodian government unveiled with great fanfare the country's first traffic overpass. The $6 million project – lit with a futuristic blue neon swoosh – was intended to ease congestion where a major boulevard that runs north-south through Phnom Penh intersects with twin bridges that cross the Bassac River, just to the east. Prime Minister Hun Sen called the Sky Bridge Project a "great achievement"  and proclaimed that it would end traffic problems in the area.

It wasn't long before commuters discovered a catch: By making it easier for motorists traveling north-south to keep going straight, the new overpass made it impossible for them to turn left onto the intersecting east-west road. The result is a mess. Now, drivers heading south who want to cross the river must first take a right and drive away for several hundred meters and then make a U-turn and head back. And motorists heading north are forced to turn right, which necessarily takes them onto the bridges – meaning that they are forced to cross the river, turn around and cross the river again. Congestion in the area is worse than ever, and the traffic more dangerous.

[vdeane]

Sounds like people aren't used to the concept of "limited access".  Though if I found the right spot, that interchange is poorly designed.

[NE2]

This? http://maps.google.com/maps?ll=11.530486,104.930694&spn=0.002397,0.004128&gl=us&t=k&z=19
Looks like a typical third-world interchange - right turn ramps with U-turns to turn left. Mexico is full of them.

[cpzilliacus]

Sounds like people aren't used to the concept of "limited access".  Though if I found the right spot, that interchange is poorly designed.

Maybe like this interchange in Arlington County, Va.?

[NE2]

Sounds like people aren't used to the concept of "limited access".  Though if I found the right spot, that interchange is poorly designed.

Maybe like this interchange in Arlington County, Va.?

Not really. That one's missing two movements, both of which can be easily made with Park Drive.

[kphoger]

This? http://maps.google.com/maps?ll=11.530486,104.930694&spn=0.002397,0.004128&gl=us&t=k&z=19
Looks like a typical third-world interchange - right turn ramps with U-turns to turn left. Mexico is full of them.

But most of the ones I've encountered in México are where there is little left-turning traffic.  The article makes it sound like there is substantial left-turning traffic at the intersection in question; and, looking at the map, it's easy to see why.  I agree that this was not well planned.  A roundabout interchange (bridge over roundabout) might have been better bang for the buck.

[NE2]

One at a major junction in Tijuana: http://maps.google.com/maps?ll=32.538483,-116.903533&spn=0.008249,0.016512&t=k&z=17
Another one where you U-turn at a roundabout: http://maps.google.com/maps?ll=32.526168,-117.015622&spn=0.004125,0.008256&t=k&z=18

[kphoger]

One at a major junction in Tijuana: http://maps.google.com/maps?ll=32.538483,-116.903533&spn=0.008249,0.016512&t=k&z=17
Another one where you U-turn at a roundabout: http://maps.google.com/maps?ll=32.526168,-117.015622&spn=0.004125,0.008256&t=k&z=18

Yes, there are a few.  And, in fact, Tijuana specifically came to mind.  But it isn't the norm across the country for high-volume left-turning movements (and I'm not too convinced that the two you show have incredibly high volumes of left-turning traffic at the missing movements).  And I struggle to think of a single one at what could be considered one of the most crowded junctions in the whole city.