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Seven Corners Realignment Concepts Presented to Public

January 14, 2014
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So what do you think? Which concept do you believe is best and why? Click on each type to tweet out your choice, or comment below.

It’s been a while since we talked about the ongoing debate over how to fix the broken Seven Corners road infrastructure to somehow take a chaotic tangle of local and major roads and rearrange them to both maintain vehicular access as well as reconnecting the community to popular retail destinations. Several years have passed since an poorly conceived aerial walkway over Route 50 was completed, and since that time pedestrian access continues to wane in the area. This past week we were provided a copy of the proposal by Kittelson & Associates, consultants who are currently conducting preliminary feasibility and analysis of the complicated intersection. They have provided 6 preliminary concepts.

Diverging Diamond Interchange

In transportation, the diverging diamond interchange has become the darling of urban arterial design: it maximizes vehicular queuing space, it splits traffic patterns into compartmentalized movements, it provides maximum efficiency in use of the right of way towards traffic mitigation. From 20,000 feet above a transportation engineer can fantasize in its absolute ability to address the traffic needs. Unfortunately, in the real world, users have to actually navigate the complicated network; often leading to last second confusion, lane changes, and accidents. Beyond this is the fact that designers of diverging diamond interchanges could save time in their end result, line up pedestrians, and just have them shot instead.

That might be a bit harsh, after all, we often see beautiful renderings like this showing the pleasant co-mingling of people and cars in a bucolic elevated plaza and park. Three value engineering sessions later and anything resembling facilities for pedestrians or bicyclists are removed because of cost savings and to improve throughput by 3% for cars. It should be noted that Kittelson & Associates is upfront in their analysis that this solution is essentially the worst of all options for pedestrian and local road users.

Split Diamond with Couplet

Well, unlike the Diverging Diamond the proposed couplet concept at least reduces the complexity of the interchange by reducing it from the tangle of multiple roads combining into a single convergence of Route 50 and Route 7. The change to Route 7 to one way and separated provides opportunity for a more neighborhood focus on widths, however the complete disconnection of the Wilson crossing of Route 50 nullifies any gain to local road users and pedestrians. It ignores the single biggest complaint made by the public, to improve the connection from south of Route 50 to north of Route 50… but it sure will help people fly off of Route 50 in their cars. Another name for a split diamond with couplet is a freeway ramp that dumps onto a local road, but then a rose by any other name…

Single Point Interchange

Well this one puts all that complexity to the vehicular user right back into the concept, but it has the added bonus of also being completely unforgiving to the neighborhood users, cutting off any connection from south of Route 50 to north of Route 50. Why this is even an option is disturbing, but then again car is king, and non-local commuters using Route 50 evidently mean more than locals.

Two Half Diamond Interchanges

This concept sounds really bad from the get go, but in terms of local access and pedestrian friendliness has the greatest promise. By relocating the major interface of Route 50 further away from the seven corners intersection, it allows the through traffic to be split from local roads and access along Wilson and Route 7. It also means those two road sections can return to a more normal and typical intersection layout which is always preferable for pedestrians and bicyclists.

Even more interesting with this concept is the proximity of the multiple new over-crossings of Route 50 to each other provides for the possibility of decking the whole area over and possibly creating possibilities for air rights redevelopment, or just pedestrian park or path improvements. This concept creates a kind of mini-belt around what could be rearranged as a central town area. This is by far the best options as a local resident and meets the criteria laid out in the Seven Corners Revitalization meetings.

Of course, with all things, the devil is in the details and residents must urge a focus on not just providing what will work for cars, but also for people. This means land use and transportation coming into focus and getting private interest for what opportunities could be made from this realignment, as far as revitalizing and creating a walkable environment with destinations for the community.

Four Corners

This concept goes halfway between the Two Half Diamond interchange concept and the single point interchange concept. It is a dilution of the concept that would benefit pedestrians and local users instead to improve access to commuters via Route 50. What is important with this concept is that, with value engineering modifications (cost cutting) and more input from commuters rather than locals, this is what the likely changes to the Two Half Diamond interchange would look like. That is why the devil really is in the details and the public needs to remain informed so that they don’t get short changed on the improvements that they have been asking for for a long time.

Jug Handle Configuration

This solution appears to be similar to Four Corners, but complicates the interface of the local roads with Route 50 by incorporating intersections instead of ramps onto the road. This is in someways the worst of all worlds. Not only does it not solve local access from south Route 50 to north of Route 50, but it also threatens to impact traffic on Route 50 itself. Route 50 should be kept separated to the greatest extent possible as it serves as one of the regions most heavily traveled east/west roads.

So what do you think? Which concept do you believe is best and why? Click on each type to tweet out your choice, or comment below.

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7 Responses to Seven Corners Realignment Concepts Presented to Public

  1. Froggie on January 14, 2014 at 3:34 pm

    I’d go either Four Corners or Jughandle. Better configured for bicycle/pedestrian connections, and better local connectivity. The DDI and SPUI options are “great” for traffic between Route 50 and Route 7, but HORRIBLE for connections to/from other streets in the area.

  2. bill johnson on January 15, 2014 at 9:04 am

    I like the design of the two half diamond interchanges. It has the most connected circular street pattern around the 50/7 cross over and looks to have the best chance of developing local improvements while not creating a bottle neck on 50 through that area.

  3. m2fc on January 15, 2014 at 9:25 am

    I’ll cross my fingers for the 2HD. Long-term the landowners need to convert all of the massive parking lots to mixed-use if there is any hope of walkability.

    Do any of these plans account for a possible BRT/LR going down 7 (presumably to meet Columbia Pike)? I think I’ve heard dreams of something like that, but I’m not sure if its realistic.

  4. JodyM on July 11, 2014 at 11:37 am

    I’m late to all of this, but do you know if they ever considered the round-about option that you were in favor or and if not, why? It looks like they have picked the Two Half Diamonds which you seemed to like so I guess that is a good thing?

    • Navid Roshan-Afshar on July 11, 2014 at 11:41 am

      VDOT/FCDOT believed a round about at this location would be too confusing… I’ll just say I disagree with that, what’s confusing are these massive super intersections they want to promote. I think the two half diamond is a good compromise, but the key will be traffic signal timing priority (whether there will be sufficient all red for pedestrians to cross safely) and if they include any value added improvements like wider walkways, better crosswalks, improved landscape. A double half diamond can be a very pedestrian friendly intersection, but it has to be done correct, you can’t value engineer out the elements that make it safe to cross and disrupt the field of asphalt.

  5. JodyM on July 11, 2014 at 11:53 am

    Thank you for your quick response! I am on one of the local neighborhood committees looking into the proposals and appreciate your blog posts and detailed thoughts. I will make sure our members know about your blog. I’d love to know your thoughts on the latest redevelopment plans and what specifically you think the local HOAs should be asking/pushing for. I know I would like to make sure they make it walkable and have green/recreational space in addition to the residential and retail they already have planned.

    • Navid Roshan-Afshar on July 11, 2014 at 12:20 pm

      I did see the reduction in density at the redevelopment site further down route 7. I’ll need to take a look into it. I think residential/retail is the way to go in that region as office is really going to be strained.

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