Inverted SPUIs?

[jakeroot]

EDIT: Oh good grief, it's real. To quote many others before me, "what is Caltrans smoking?"

What does Caltrans have to do with it?

Uninformed Seattleite is uninformed.

What is Santa Clara County smoking!?

It kind of makes sense to me.

To build a typical diamond interchange would require the acquisition of a significant amount of land around each proposed interchange, most of which are business parks and retail shopping centers.  The use of the inverted SPUI and the elimination of one of the four travel lanes in each direction would cut down on the amount of additional land needed and thus keep costs down.

My concern is the resemblance to the Westside Highway, and my general distaste for left-side entrances and exits.

I'd rather see two through lanes in each direction with not as many junctions (ideally, half diamonds at Monroe and Arques, with frontage roads in between).

[bugo]

This interchange is similar in concept (but was probably just stitched together from the time that I-35 didn't exist south of this interchange).

[myosh_tino]

My concern is the resemblance to the Westside Highway, and my general distaste for left-side entrances and exits.

I'd rather see two through lanes in each direction with not as many junctions (ideally, half diamonds at Monroe and Arques, with frontage roads in between).

Two lanes probably won't cut it but I think they could get away with 3 lanes.  While I agree that left exits and entrances on freeways are a bad idea, Lawrence Expwy is what I would consider a major arterial that has a posted speed limit of 50 MPH.  Keep in mind that the signals at the US 101 interchange and at Duane Ave will not be removed.

Actually, looking at the project website it looks like the county has decided to go with the inverted SPUIs plan but to depress the roadway some 30 feet so all crossing roadways and the train tracks would retain their current elevations.  The plan also calls for retaining the 8 travel lanes and add a 6 ft sidewalk and 6 ft bike lane on each side of the road so I guess there's going to be some pretty extensive property acquisition.

Project Website: http://www.sccgov.org/sites/rda/plans/Lawrence/Pages/legs.aspx

[JKRhodes]

I suppose the HOV exits for 3rd St and 5th Ave on I-10 in Downtown Phoenix could be considered "Inverted Half-SPUIs," with the latter having an "inverted frontage road" through option to access 3rd Ave.

[ekt8750]

I-76/South Street Interchange in Philadelphia

Originally built in the 1950s with the much of the on/off ramps reconstructed within the last decade as part of the South Street Bridge replacement project.

The Schuylkill Expressway has got to be one of the most diabolical open-air torture chambers ever designed by man.  Lanes that end and begin at random, with them exiting and entering on both sides - lose a right lane, and gain a left, wash, rinse, and repeat at the next interchange, then reverse it a half-mile later.

The South St, 30th St/676, and Montgomery Av interchanges have to be the worst designed feats of engineering ever imagined. The bottlenecks at South St and 30th are the worst and for no reason other than some idiot that thought left side on ramps were a good idea.

You know it's bad when the best part of that freeway was the part built by the DRPA 

[jeffandnicole]

I-76/South Street Interchange in Philadelphia

Originally built in the 1950s with the much of the on/off ramps reconstructed within the last decade as part of the South Street Bridge replacement project.

The Schuylkill Expressway has got to be one of the most diabolical open-air torture chambers ever designed by man.  Lanes that end and begin at random, with them exiting and entering on both sides - lose a right lane, and gain a left, wash, rinse, and repeat at the next interchange, then reverse it a half-mile later.

The South St, 30th St/676, and Montgomery Av interchanges have to be the worst designed feats of engineering ever imagined. The bottlenecks at South St and 30th are the worst and for no reason other than some idiot that thought left side on ramps were a good idea.

You know it's bad when the best part of that freeway was the part built by the DRPA 

And yet, has the lowest posted speed limit.

[ekt8750]

I-76/South Street Interchange in Philadelphia

Originally built in the 1950s with the much of the on/off ramps reconstructed within the last decade as part of the South Street Bridge replacement project.

The Schuylkill Expressway has got to be one of the most diabolical open-air torture chambers ever designed by man.  Lanes that end and begin at random, with them exiting and entering on both sides - lose a right lane, and gain a left, wash, rinse, and repeat at the next interchange, then reverse it a half-mile later.

The South St, 30th St/676, and Montgomery Av interchanges have to be the worst designed feats of engineering ever imagined. The bottlenecks at South St and 30th are the worst and for no reason other than some idiot that thought left side on ramps were a good idea.

You know it's bad when the best part of that freeway was the part built by the DRPA 

And yet, has the lowest posted speed limit.

And we all know why lol

[dfwmapper]

What does US 75 and Parker Road in Plano, TX, count as? US 75 and the frontage road run at-grade, and Parker runs on an overpass, with no direct connection between the frontage road and Parker like your normally see in Texas. Left turns are SPUI-style with ramps connecting to/from the left side of the frontage road to Parker. Previously, there were 4 L shaped RI/RO ramps connecting Parker to the frontage road, but it was rebuilt into a SPUI in 2009/2010 because traffic was murder with all the commercial development along the frontage road in the early/mid 2000s (hello Costco). The old ramp locations now serve right turns only.

http://goo.gl/maps/AXC5W

[JKRhodes]

What does US 75 and Parker Road in Plano, TX, count as? US 75 and the frontage road run at-grade, and Parker runs on an overpass, with no direct connection between the frontage road and Parker like your normally see in Texas. Left turns are SPUI-style with ramps connecting to/from the left side of the frontage road to Parker. Previously, there were 4 L shaped RI/RO ramps connecting Parker to the frontage road, but it was rebuilt into a SPUI in 2009/2010 because traffic was murder with all the commercial development along the frontage road in the early/mid 2000s (hello Costco). The old ramp locations now serve right turns only.

http://goo.gl/maps/AXC5W

I'd call it Very Texas  ... a SPUI with the advance u-turns and grade separated service roads.

[kphoger]

Yep. Just a SPUI. Some turnarounds thrown in because Texas is awesome, some elongated right-turn slips for whatever reason, other than that it's just run of the mill.

[jakeroot]

some elongated right-turn slips for whatever reason

At least two are because of the previous squished cloverleaf. Perhaps the other two were for symmetry.

[bugo]

Both right turn offramps meet the cross street at a 90ish degree angle. Why don't they merge into the street? There is no reason to turn left at these intersections.

[jakeroot]

Both right turn offramps meet the cross street at a 90ish degree angle. Why don't they merge into the street? There is no reason to turn left at these intersections.

Functionally, it's like a speed bump. Meeting the cross street at a 90ish degree angle sort of forces a stop. I think they're ridiculous, FWIW, but I understand the purpose.

But like I said before, those ramps are from the previous interchange.

[Otto Yamamoto]

NY 9A at NY 117, unsure of the date that was built, this has the bonus of the Taconic State Parkway running immediately adjacent, so northbound NY 9A and the southbound Taconic pass under the same bridge.