Wednesday, December 23, 2015

PV109 Access Permit: The Three Speeds

The Albertini subdivision at 109 Pleasant Valley Road is, to put it politely, problematic.

There are three kinds of speed involved when considering an access permit, and in any situation where road design is at issue: design speed, operating speed and posted speed. One of the goals in engineering a road is to ensure that these three measurements are roughly equal. The process is supposed to go something like this: Figure out how fast you want traffic to flow, design the roadway to that target design speed, study the actual operating speed (85th %ile), set the posted speed to match the operating speed.When these three speeds converge, the road is relatively safe and comfortable.

Especially since reconstruction of the section of Pleasant Valley Road at Mountain Road, the posted speed along Pleasant Valley Road is not consistent with the operating speed of the road. It is arbitrarily too low.

The Vermont Agency of Transportation's Traffic Impact Study Guidelines succinctly explain the problem of arbitrarily low posted speed limits:
Much like installing traffic signals, reducing speed limits is often seen as a panacea for traffic ills. Speed limits must be set in accordance to the MUTCD. The MUTCD, in section 2B.13, requires than an engineering study be completed in accordance with established engineering principles. It states that the speed limit should be set within 5 mph of the 85th percentile speed of free-flowing traffic. Other factors which may be considered along with the 85th percentile speed are road characteristics (geometry), pace speed, roadside development and environment, parking practices and pedestrian activity and reported crash experience.
Since the 85th percentile speed is quite often higher than the existing speed limit, it is difficult to justify a lower speed limit. Arbitrarily setting a lower speed limit is not an effective method to reduce driver speeds – drivers select their operating speed by “feel”, with little regard to the posted speed limit unless there is active enforcement. Assuming that the majority of drivers are prudent and safe drivers, the 85th percentile speed is deemed a reasonable speed limit unless there are factors which strongly suggest that drivers are making poor decisions at that speed.  
This idea that design speed, operating speed and posted speed should be equal is a fundamental notion in traffic engineering. A lot of design decisions and traffic analysis rely on -- and flow from --this idea. When these three speeds are not in agreement, bad things happen.

That is why it is so disappointing that the consultancy attempting to develop a subdivision at 109 Pleasant Valley Road (PV109) did not immediately point out the discrepancy between posted and operating speed.

Here's how easy it is to discover:
1) Point your browser to the CCRPC database
2) Under Traffic Data, click on Map
3) Click on Underhill in the map of Chittenden County
4) Click on the Underhill Center region of the town, it will look like this:

Each of the dots represents a traffic count location. Click on the one near Pleasant Valley Road at Mountain Road, UHIL16. Then click on "Speed Profile" (more details available by clicking "Download Count"). You will see that even in 2005, before the straightening, flattening and widening project, the operating speed (85th%ile) is well above the current posted speed of 30mph.

At this point, knowing that the posted speed is 30mph, alarm bells should be ringing in the mind of a traffic engineer. But that's not what happened.

Trudell Consulting Engineers (TCE) has repeatedly understated the traffic and safety issues with the proposal to construct an intersection for the proposed Applewood Lane. All the while many, many people have expressed concern about the proposal to construct an intersection on the inside of the blind corner south of Mountain Road. Even now, TCE has proposed a close -- too close -- offset-T intersection.  At earlier stages of the process, they attempted to substitute posted speed for design speed and argue that a 4-way intersection with Mountain Road is not feasible. Now, with the 4-way design complete, they have concocted a "possible class III wetland" and lean on it as a rationalization to continue to push for the offset-T.

Sadly, this lapse of engineering judgement and ethics is not an isolated incident.

Monday, February 16, 2015

Right to Farm

Right to Farm is mentioned in the draft plan. But because Vermont is a Dillon Rule state, the state's right to farm law, which has been in place since 1981, is the final word on right to farm.

Underhill's zoning has a role in prohibiting non-farming uses, and permitting farming uses, but it already does that.

It's All About the Nuisance

"Zoning generally overrules nuisance. For example: if a factory is operating in an industrial zone, neighbours in the neighbouring residential zone can't make a claim in nuisance. Jurisdictions without zoning laws essentially leave land use to be determined by the laws concerning nuisance."[wikipedia]

This is a problem because it is impossible to imagine all of the possible future uses of land, much less write prescriptive zoning rules that elegantly address the many conflicts that can arise. And it is terribly inefficient and usually ineffective to try to right the wrongs of harmful, nuisance, noxious uses.

Underhill had for a long time a very good solution: no-growth policy befitting an exurban fringe town, stable zones with stable densities, limited permissible uses, broad conditional use review. This allowed for the flexibility of nuisance law with the anticipation of zoning. Yes, the regulators and townspeople need to be vigilant. But, in a no-growth town like Underhill, it is not a burden and works well by allowing gradual, ad hoc use conversions and straightforward, conditional control of noxious uses.

Friday, January 16, 2015


Chittenden Regional Planning Commission (CCRPC) wants Underhill to know think that the future is booming. In a presentation to the Underhill Planning Commission, we hear: 
"If the past is any indicator, Chittenden County will feel the pressure from a majority of that growth. Woods and Poole estimates that Chittenden County may see 50,000 new residents by 2035 (refer to the first figure in Section 2.1). "<link>
And this is reinforced in the ECOS plan with loud graphics:

2013 Chittenden County ECOS plan 1.2 Vision, p.5
30% population explosion!!!! Whoa, take it easy. This bears more scrutiny. CCRPC has a history of getting it wrong. In 1976, they said the population in 2000 the Chittenden County population would be 182,149, 24.3% above the actual population which was 146,571. In 2001, CCRPC projected an annual growth rate of 1.4%, 2000-2010, which would be a population of 168,439 in 2010. With just a nine year horizon, they still missed the actual 2010 census of 156,545 by 7.6%. If the past is any indicator, CCRPC has overstated population projections.

In the final version of the ECOS plan, long after the message of growth had been implanted, and even after long-time planner Tony Redington mocked CCRPC for inflated population projections, only an inoculating caveat is added. But the claim of high growth remains -- and the boldface.
"Woods and Poole estimates that Chittenden County may see 50,000 new residents by 2035 (see Figure 2 in Section 2.1). These numbers are only projections at two different levels of geography and will very likely be inaccurate, but still they give us a sense of the direction of the market demand for jobs and housing in our region." -- Chittenden County ECOS Plan, 3.0 Introduction, p.78
The bald face text continues with a tell-tale denial that suggests exactly what the plan is about:
"This Plan is not a plan to achieve growth, rather it is a plan that recognizes that there are many external factors over which we have little control locally." -- Chittenden County ECOS Plan, 3.0 Introduction, p.78
At least, they are not crooks, but they are phishing for suckers. Underhill planning commissioners have been exhorted by regional planners to get more housing -- a lot more. But before swallowing this hook, line and sinker, Underhill ought to look to some other sources and apply some common sense.

As Art Woolf pointed out in a January 8, 2015 column in the Burlington Free Press, Vermont's population is flat right now. It's a return to normal. "If history is any guide, small towns will certainly experience depopulation, just as they did through most of the late 19th and first half of the 20th century. It's very likely to also be the experience of most of Vermont's larger towns and cities, especially outside of northwestern Vermont," he wrote.

The only state population projection available comes from a report prepared by the VT Agency of Commerce and Community Development, which evaluated two scenarios using migration rates derived in two different decades, the 1990s and the 2000s. Using the more recent 2000s data, Chittenden County population increases by just over 4.1% -- not 30% -- while Underhill's population shrinks by 3.3% from 2010 to 2030. Not surprisingly, the greatest growth is in suburban towns near I-89.

VT Agency of Commerce and Community Development <link>

For comparison, a similar state report (methodology), prepared in 2000, projected 2010 Chittenden County population at 157,471, an estimate error of less than 0.6% for the decade -- an order of magnitude more accurate than CCRPC.

At the same time, Chittenden East Supervisory Union (CESU) protests (a bit too much, especially given their failure to produce any projections) that school population is dropping, echoing similar claims by the Vermont Agency of Education.

But the US Dept. of Education thinks that unlike all surrounding states, enrollment in Vermont will rise modestly over the next few years. Not surprisingly, the South and West have strong enrollment growth.

Public School Enrollment -- National Center for Education Statistics

And the Vermont Housing Finance Agency has a similar projection for school-aged enrollment.

Housing and Vermont's School Enrollment -- Vermont Housing Finance Agency

Note the source for this data, the US Census Bureau. They don't get any more rigorous than that. What's interesting about these numbers is how much lower the state's school enrollment is than the number of school-aged kids. Already, in 2004-5, the statewide enrollment was 93,813, well below the projected bottom of the Census Bureau curve of school-aged kids. Maybe the claimed education crisis is a marketing problem -- not a shortage of kids or excess of schools. If the state's schools could recapture market share, it looks like they'd enjoy increasing enrollments for more than a decade. There are more mysteries to be solved in the enrollment data: The US Census doesn't jibe with the Vermont Agency of Education data, which doesn't agree with the US Department of Education data. And we are not talking about small numbers. It's thousands of kids apparently unaccounted.

All states and the District of Columbia produce and report population projections to the US Census Bureau, except Vermont. What should that tell us about the conflicting population projections of CESU and CCRPC? The projections that they use seem to be very much in line with their respective agendas, school consolidation (pardon me, "redistricting") for CESU, and housing boom for CCRPC (sorry again, "smart growth").

State-Produced Population Projections -- US Census Bureau
New York has a nice set of charts, including a sequence of population pyramids that illustrate the passage of baby boom echoes and a projected population decline after 2030.

With all of the sloppy numbers from CCRPC underpinning the whole regional plan, what should we do?:
  • Regional planners lack credibility. Challenge them or ignore them, but don't let them push us around.
  • Plan for non-increasing population.
  • Plan for open space and conservation. That is Underhill's true role in the region.