Developing a regression estimator for Acadia National Park carriage roads 2014 - 2015

Jacobi, Charles

From executive summary: "The introduction of the Eagle Lake Bicycle Express van service from the Bar Harbor Village Green to the Eagle Lake carriage road access in 2006 changed the number of visitors entering at that location. Because of this, we conducted our third set of carriage road censuses in 2014 - 2015. The purpose of the censuses was to develop a new regression equation to estimate overall daily carriage road use by pairing the census counts with traffic counts from an electronic trail counter on the Eagle Lake carriage road. Daily traffic counts are then plugged into the regression equation to estimate overall daily use for July and August. These daily use estimates are then compared to a visitor capacity standard of 3,000 visitors per day to determine if the standard is violated. We completed 10 of 14 scheduled censuses over the two seasons. The 2014 - 2015 regression resulted in an r2 of 0.86. The slope of the regression line was 2.16 and the intercept 587. The significance of the regression (F statistic) was 0.000105738. These results mean we can apply the regression equation y = 2.16x + 587 (x=trail counter count, y= daily use estimate) with confidence from 2006 through 2015 and for the next 5 - 10 years barring other changes in how visitors access and use the carriage road system. Compared to the most recent regression equation, the new one will estimate less use because its coefficient and intercept are smaller. This finding is consistent with the reason we decided to conduct another set of censuses-the Eagle Lake Bicycle Express van delivering several hundred more bicyclists per day to the Eagle Lake Boat Launch and inflating estimates. Use at all other carriage road entrances did not increase at the same rate, but the regression equation assumed that it did. As mentioned, we will apply this new equation to 2006 - 2015 data. We expect that it will show a couple of things. First, it will reduce daily estimates of carriage road use significantly. Because of this, we expect it will also show that we approached or exceeded our standard of 3,000 visitors per day less frequently than previously estimated. And second, it will still show an increase in carriage road use over that time period, but not as much as previous estimates. This result may appear confounding given evidence of an increase in overall park use since 2006 and the anecdotal observations of many park staff that carriage road visitation has also increased. But we believe there is no inconsistency. It is just that overall carriage road use has probably not increased as much as previously thought, but it has increased. We will know more when the new regression equation is applied to the past ten years of data."

Developing a regression estimator for Acadia National Park carriage roads 2014 - 2015

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