New Mobility Northwest

Last month we had a great discussion about the Grand Parkway. I’ve been thinking about it a lot since then, and I decided that I wanted to make a little bit more elaborate case for an alternate. Prior to revising the Grand Parkway, I wanted to take some time to write about some useful terminology and theory that I hope will help make this second round of conversation even better. Today we’ll start with a look at the Grand Parkway, and in my next post we’ll move on to a more detailed look at the Katy Prairie and its future.

Earlier Conversation

I’m going to assume that everyone is familiar with the Grand Parkway concept – a massive new outer loop road around the Houston metro area. The idea is that as the city continues to expand we need more loops to keep it all connected. These new loops would theoretically provide new avenues for growth, “just as the IH-610 did and Beltway 8 did.”

There are some problems with this argument, however. First, it’s not clear that a radial loop pattern is even the best freeway system for polycentric urban areas. In his book about Houston Freeways (pg 61, available online), Eric Slotboom makes a compelling case that a grid-like freeway pattern would have served Houston better. A gridlike freeway system is designed to connect multiple centers, rather than concentrate activity on a single center. Houston has clearly become a polycentric city, and while we cannot simple move the old freeways, we can build new ones on a different paradigm.

One of the arguments against the Grand Parkway as it’s currently planned has been the lack of popular support for it. Last month, some of the discussion revolved around the idea that the Grand Parkway was “too visionary” for people to understand, that this was the only reason that people didn’t support it, and that the Grand Parkway was simply the next logical step to allow growth out of new urban centers like the energy corridor. That’s grid-like thinking… the problem is the proposed Grand Parkway isn’t designed as a center-connecting “grid”, it’s designed as a city-bypassing “loop”.

Linear and Geometric

The simplest problem with the Grand Parkway as it’s currently concieved is that the area it is intended to serve is imposssibly large. Let’s look at a simple visual example of this.

In the image above the red line represents the proposed route of the Grand Parkway. The black boxes represent an area approximately the size of the loop.

Generally the area “inside the loop”, or “the Inner Loop”, is considered Houston’s urban center, this is represented by the red box in the image. The Inner Loop has a population of aproximately 600,000. It is crossed by 7 freeways, and of course, the loop. The average population density is about 6,500 people per square mile.

This area, Houston’s densest overall, is significantly less dense than many other entire cities in the US, such as Los Angeles (~8,200/sqmi), Washington DC (~9,500/sqmi), Chicago (~12,500/sqmi). In other words, it’s not that dense. The Loop is home to both skyscrapers and cottages, and in my experience (as an inner looper) it’s considered to be a great place to live, and not terribly crowded.

The area between the loop and the beltway is shown in yellow boxes. As you can see this area is 6 times larger than the inner loop, though it is less dense. Some of the areas in yellow, in particular due south of the Loop, are scarcely populated. On average each of these areas is crossed by two freeways.

The area between the proposed Grand Parkway and the Beltway is about 14 times larger than the area inside the loop. Most of this area is barely populated, and most of these sectors are covered by only one freeway.

If the area between the beltway and the loop were built-out like the medium-density Inner Loop, it would be home to 3.6 million people. This would mean 4 million people living in Houston inside the Beltway. I don’t know what the population actually is between the loop and the Beltway, but since the entire Houston-Galveston metro region is currently projected to be home to under 6 million people, it’s clearly a lot less developed than that.

If the area between the proposed Grand Parkway and the Beltway were as developed as the Inner Loop, the area would be home to 8.4 million people. Add this to the 4 million living inside the Beltway (if the density level were the same) and Houston would be home to 12.4 million people.

Clearly, there is no way in this universe that 8.4 million people are going to be efficiently served by a single freeway. How, then, is building the Grand Parkway “just like building the loop” or “just like building the Beltway?”

It’s not.

Where does it go?

The first segment of the Grand Parkway, from Katy to Sugarland, made sense. That piece of road dramatically shortens the trip between two of Houston’s leading suburbs, links I-10 and Westpark Tollway, and serves an already large and rapidly growing population anchored by Sugarland’s rapidly expanding employment base.

Segment E doesn’t go from anywhere to anywhere – but it could. Last month I posted a first look at a revised Grand Parkway Segment E designed as a connector between Katy and Cypress – in other words, a road people would actually use. It’s critically important if we’re going to invest in any major infrastructure that we know what we need and build accordingly. Houston doesn’t need Tier 1 system on its outer edges, because it wouldn’t connect any independent market areas. Houston needs a Tier 2 system to provide a reliable inter-suburban link. And while improving the connection between Katy and Cypress is a good idea, improving the connection from Katy and Cypress to Spring is an even better one.

What should we do instead?

Today I want to look at a more refined concept that takes some of the broader area concerns into consideration. Here’s an outline of my concept for improved mobility in Northwest Houston:

• First, let’s stop thinking of Grand Parkway as a conventional freeway, and start thinking of it as a new iteration of Allen Parkway. We don’t need (or want) a continuous frontage road due to the extremely low density strip development it attracts and the additional cost. Instead, at major intersections the outside lanes of the Parkway can become access lanes that intersect with the crossing street, while the mainlanes stay grade-separated. A great example would be the Allen Parkway and Waugh Drive intersection. This is an extremely space and cost effective intersection configuration, particularly for a lower demand area.
• Second, lets remember that if the area around the Grand Parkway does develop into the dense, mixed-use home of 12.4 million people, we’re going to need a hell of a lot more than one mega-freeway to serve it, so in no forseeable reality can Grand Parkway serve as the only major through route for this vast area, and designing it with that idea in mind is foolish.
• Ideally the parkway needs about a 1 lane median (for safety more than anything else), and 2 lanes each way to start with. Enough ROW could be preserved to add continuous third lane in the future. At intersections there should be an exit-only lane which leaves the main-throughway and intersects with crossing streets.
• At some minor intersections, at-grade crossings could be allowed. Consider Allen Parkway and Dunlavy, or Allen Parkway and Taft. In general I would suggest that these be highly limited, but I think they could serve as acceptable, low cost access points for at leat 15-25 years worth of demand growth. Again, just buy enough ROW if there’s reason to expect a bridge will be needed in the future.
• Lastly, Grand Parkway should not, under any circumstances, be built without significant improvements made to the SH-6/FM1960 corridor. That corridor already has massive ammounts of traffic and would benefit tremendously from a conversion to an Allen Parkway like street. Local access could be maintained within the existing ROW, and cross access would be noticably improved if through movement didn’t need a light cycle any more. Other corridors could also be improved, and the more corridors we enhance the better transportation will be.

If you flip through the gallery below, you’ll see that idea.

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Here are the highlights of why I think this is a much better concept than what exists on the table today:

• If we use Grand Parkway as a Katy -> Cypress -> Spring connector then it will really benefit the existing communities rather than serving exclusively to open up new areas for leapfrog development.
• Designing the road as an multiway like Allen Parkway creates both an excellent traffic conduit and the opportunity for excellent interfaces at major intersections, which provides a natural opportunity for viable town centers to develop at these strategic points.
• Following Spring-Cypress Road saves the city and the county the enormous cost of acquiring Right-of-Way for a road that isn’t needed in this generation.
• Spring-Cypress from 290 to 249 is an excellent choice for a multiway because it’s got enough ROW and has very few driveways, except at intersections where there would be access lanes anyway.
• From 249 to 45 there are a few spots where the design would be more complicated, but there are plenty of good options, including shifting the route to cut through undeveloped areas parallel to the exising Spring-Cypress road in some short stretches where it passes through large-lot areas with more driveways. There are also alternate routes it could follow.
• Reducing the expenditure on Grand Parkway could allow us to shift funding to improvements in the SH6/1960, 529, 249 and other corridors, which would be far more valueable today than a distant outer ring road.

Overall, I think this concept is a worthy challenger to the existing Grand Parkway concept. Not only should it cost less and serve more people, it also is designed to create a better urban network, which means more opportunity for the development of coherent, walkable and transit-serviceable neighborhood centers. I’ll elaborate on that more in my next post.

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So that’s my idea for new mobility in Northwest Houston. I’m looking forward to the diverse reactions I’m sure this one is going to get, dive right in and let me know what you think by leaving a comment!