Comments on the Traffic Study
The city funded a traffic study in 2019, to assess the impact of the proposed road. The study was carried out with minimal resources, but it was hoped that it would include sufficient information for the council to make a decision.
One of the findings of the study was that there will be a lot of cut-through traffic. Specifically, the desire to avoid the congested US192/Minton intersection would motivate many drivers to use the new road as a shortcut, especially during rush hour.
The purpose of this page is to argue that the reality will be even worse than depicted in the study.
You can read the study report here:
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There are several reasons to suspect that the study underestimates the negative effects of the new road.
First, the analyst approached the issue of cut-through traffic by measuring the driving time with the current roadway configuration; then estimating the driving time after construction of the new road, and comparing the two numbers. If there was not a significant improvement, it was assumed that the drivers would not take the new road as a shortcut. Experienced drivers know that this is not a strong argument, because when under pressure (late for work, frustrated with traffic, angry at other drivers) we often take whatever shortcut presents itself; no transit time measurements are available to us, and we would probably ignore them if they were. This is a well-documented phenomenon. (See cut-through traffic page.) Therefore, it is reasonable to expect cut-through traffic higher than predicted in the report. Remember, too, that these drivers are notorious for speeding and accidents.
Perhaps a more significant comment is that the actual traffic counting was very limited, presumably because of funding limitations, and was apparently unrepresentative of normal conditions. Since traffic fluctuates in a more or less random way, we can't rely on a single measurement over a short interval of time to give us realistic numbers that typify normal conditions. What is striking here is that the counts on Henry are so much lower than the counts made by the county (SCTPO). The county measurements, covering counts taken over several years, indicate that the Level of Service is consistently LOS = E (where A = Best, F = Worst). However, the city traffic analysis shows all LOS = A, B, or C. Likewise, if you look at the hourly data, the numbers for a supposedly typical rush hour count are much higher in the county data than in the city data. For example, in the county data, the average hourly rate (averaged over two hours) was 1022 vehicles, whereas in the city data it was 724 vehicles. This is a dramatic difference, almost 50%. Given that the county data is consistent over several years, whereas the city data was a one-day measurement, the county data would appear to be much more credible.
Please note also that the county data is from a disinterested organization, whereas the city traffic study was funded and managed by city staff, whose stated goal was to support the project, and whose preconception was that there would be no problem. Even Mayor Rose has commented that he has never seen a traffic study that failed to support the conclusions desired by whoever foots the bill.
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Yet another factor is the time frame that was analyzed. The study only projects out to 2023. The road cannot possibly be completed prior to 2023. The engineering group (Neel-Shaffer) that did a conceptual design in 2012 projected 25 years in advance, which seems appropriate. Traffic levels are increasing a few percent every year in this region because of rampant development. The Minton Road Study projects future traffic as high as 51,000 cars per day on Minton Road in 2045. The study should address the future, not just the present. The use of realistic future projections (available for free from SCTPO) would have led to much different outcomes.
Most puzzling is the fact that the study does not mention the lessons that should have been learned from the experience with cut-through traffic on Trend Road. As discussed on the cut-through traffic page, the Trend Road story makes a powerful case that cut-through traffic on the Doherty/Heritage Extension may be downright overwhelming. The study should have considered this information, since it is directly applicable.
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Finally, if you believe that Henry Avenue is not a high traffic street, please take a look at this short video:
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Local residents confirm that this condition on Henry occurs often (see People Speak page).
Considering all of these factors, it is likely that the cut-through traffic will be higher than predicted, and the total traffic will be higher than predicted.
That being the case, it also follows that it would be quite risky to implement the new intersection without traffic lights.
