Star Ford

Essays on lots of things since 1989.

A few things about an intersection

on 2013 December 8

These are some comments on a local street upgrade project.

Summary of the scope for people not familiar with the project: The Indian School property is one of the only pieces of sovereign native land inside a city, and it is being redeveloped into some huge office buildings and hotels and retail. The city has agreed to do street improvements outside of the land. Traffic growth is projected, and so this project’s scope is to improve the two arterial streets that border the Indian School property and the intersection of those two streets.

The main question is what are we trying to achieve? A lot of people seem to be wondering why we should do anything. My answer (which is not exactly the official reason) is that the following problems exist, which should be remedied:

  • Pedestrian access is incomplete and treacherous in places; in the worst case there is a bus stop in a place where there is no pedestrian access at all.
  • The roads are designed without modern traffic calming and management techniques, meaning no medians, and so wide in places that it promotes speeding. (safety in general)
  • The area is dilapidated in spots, and some well placed repair of streets and other public spaces could help in the general realm of urban revitalization – making it more pleasant to be in.
  • There will be an estimated 40% increase in traffic which needs to be accommodated (maybe – see below).

Here are a few problems in the current thinking that the plan should address:

Problem 1: Demand increase is suspicious justification

The valley has quite low traffic levels generally, and the engineers predict about a 40% growth in the segments studied. It’s not clear where that growth is from. For example, they project growth on the segment leading away from the new employment center in the AM peak (from 520 to 700 cars/hr), which obviously cannot be explained by the employment center itself (because it generates no origin traffic in the morning), so therefore it must be explained by an estimate of area-wide growth trends. But I doubt whether the valley will experienced trends of that scale because it is bounded and already fully built out, and has been very slow to change.

The Indian School land (blue with heavy outline – partially developed) and the larger high intensity employment center (pink with thin outline). The green arrow shows one of the legs with increased projected travel demand.

employment center

The streets in question are apparently underused at present, so even if you believe the growth prediction, it’s hard to believe that they can’t accommodate the increase. For example, in peak hours at that intersection, you virtually never have to wait more than one light cycle and rarely have to queue more than 2-3 cars. So the whole idea that capacity increases underpin the need to rebuild the whole intersection is suspect.

Problem 2: Plan lacks coordination with travel demand management and mode shifts

In theory, fixing the things bulleted above is synergistic and can cause a shift in usage patterns: more people will walk and bike, for example. There’s a collection of benefits – health, efficiency and safety being among them – that are collectively the goals of things like the “Great Streets” ideas that this project is based on. But that theory only works if all the pieces are there. By contrast, there’s a nice sidewalk by the Sam’s Club on Renaissance Blvd, but no one uses it because there is no place you would want to walk to.

A “nice” sidewalk but useless because it is is an auto-scaled environment:samsclub

To avoid that problem, more pieces of the whole theory have to be included: destinations, connectivity, transit, and intermixed residential and business uses. The reason people walk in Berkeley (as an example) is not just because of sidewalks; it is also due to the density, intermix of uses, and transit availability.

While this is getting beyond the project’s strangely limited scope, it’s worth mentioning a couple things that would help a lot, and maybe by thinking about these things – even if they are not in scope of the current project – they will orient the decisions of the current project towards being able to achieve them later. One is shared parking, so you can park once and go to multiple places – a feature that reduces trips and therefore reduces the need for road capacity expansion. The Walgreen’s parking lot is basically never more than a third full, but that parking lot is not interfaced to any other destination. If parking were distributed and connected, more of those Great Streets goals would be met.

And perhaps even more important is the funneling of traffic due to dead ends and the bizarrely convoluted road layout. A principle of accommodating traffic growth is distributing it, not collecting more it all together. To that end, the North frontage road should connect to the employment center in multiple places, and be a two-way street if possible. This would give those people entering the employment center from the highway more options, and would allow scaling back the artierials somewhat. Internal connectivity is also very important for distributing traffic and for walking. The more neighborhood connections there are, the less the cut through traffic impacts any one single street.

More street connections distribute traffic:connections

And, with a million square-feet of office space, would a couple express buses from different parts of the city be reasonable, as a way to reduce car demands in the area? Connecting major employment centers by transit ought to be a major goal of the city, which can happen quicker than land development, and can be partly paid for by reduced parking requirements.

Problem 3: Potentially omitted sidewalk

The option of not having a sidewalk on the north side of Menaul is problematic. It isn’t out of the question, as the properties on the north side are not accessed from Menaul anyway, and it is possible to have a sidewalk on only one side. But the bus stops would need to be somewhere else and the pedestrian connections changed to access those stops.

An actual bus stop requiring you to wait on the street or climb a dirt hill to get out of traffic:

bus stop

Problem 4: Blocked left turns

The housing north of Menaul consists of about 120 houses in a “pen” – only accessible from 12th and Menaul (ditches block the other sides). The most important travel direction for people in that pen is Menaul eastbound, as that connects to the highway and a larger part of the city than the other directions. Blocking that direction of turning from 10th south onto Menaul east would mean that all the traffic would have to go through the bottleneck of the 12th/Menaul intersection.

The perceived downside of allowing all turns is that it promotes neighborhood cut-through. However, distributing traffic is a good thing, so ideally we should open up more cut through options to spread it out more. The speed of the neighborhood traffic is another issue, which can be managed by narrowing and curving the lanes.

The landlocked “pen” with the left turn that allows traffic to bypass 12th/Menaul intersection:

the pen

Problem 5: Overall priorities

Construction is scheduled for 2014, but this is strange because there are places with an immediate need, major safety problems and backed up traffic – 4th and Montano is an obvious example. I think we need to concentrate money where the needs are more pronounced, and let this one slide until we have a more compelling plan whose reasoning is more valid. In the meantime, the bus stop location, which is the single more important thing that needs to be fixed, could be moved to a less hostile location, like the corner of 10th street. (Yes I know buses aren’t supposed to block intersections when they stop, but this bus is a rare thing and this would be a cheap and instant solution until the whole street gets rebuilt.)


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