Understanding the Count Data

Uses vs. Users

One of the most important points to note about the count data is that it shows number of uses or trips, not numbers of users or numbers of total visitors.  Trail users will be counted every time they pass the counter, meaning that a trail user who takes an “out and back” route will be counted twice. All of the trail sections counted likely have a high percentage of these types of users, but it is difficult to calculate the percentage to be used in corrections. The published data from the Census therefore represents the number of trail trips or uses not trail users.

Adjustment Factors

There are some limitations to passive infrared counter technology.  First, the counters are not capable of determining the type of use so pedestrians, bicyclists, and any other user are indistinguishable in the count data.  Second, there are multiple conditions that can result in error in the data including undercounting due factors such as multiple people passing the heat sensor at the same time, traveling side by side, bikes passing the counter too fast, mechanical error, or technical failure.

In order to account for the potential differences between the actual number of trail uses and what IR counters register, an adjustment factor is used to correct the raw counts for each trail. Adjustment factors are determined by multiple hours of manual counts. To complete a manual count, a volunteer is situated within view of the IR counter and records the actual number of people who pass by the counter. The manual counts are compared to the number that is recorded on the counter for that same hour to determine the adjustment factor.

Adjustment factors for data posted on the data dashboard for 2022 and earlier used adjustment factors developed from manual counts for all years through 2022. Correction factors for 2023 and later are updated with the addition of the current year manual counts.

Permanent IR Counters 2023

Adjustment Factors
Trail Name/Counter Location Town  2022 and prior 2023  
Air Line Trail East Hampton East Hampton 1.30 1.30
Air Line Trail Portland Portland 1.20 1.03
Air Line Trail Thompson Thompson 1.92 1.92
Air Line Trail Willimantic Willimantic 1.69* 1.69*
Bluff Point Trail Groton Groton 2.37 2.30
Charter Oak Greenway Manchester Manchester 1.47 1.49
CTFastrak Trail New Britain New Britain 2.65 2.65
Farmington Canal Heritage Trail Cheshire Cheshire 1.27 1.31
Farmington Canal Heritage Trail Hamden Hamden 1.53 1.52
Farmington Canal Heritage Trail New Haven New Haven 1.72 1.73
G&S Trolley Trail Groton Groton 1.06 1.06
Hop River Trail Bolton Bolton 1.76 1.71
Hop River Trail Vernon Vernon 1.43 1.39
Larkin State Bridle Trail Oxford Oxford 1.03 0.99
Middlebury Greenway Middlebury 1.50 1.51
Naugatuck River Greenway Trail Derby Derby 1.69 1.63
Norwalk River Valley Trail Redding Redding 1.00 1.80
Norwalk River Valley Trail Wilton Wilton 1.54 1.45
Riverfront Recapture Trail East Hartford East Hartford 1.45 1.45
Riverfront Recapture Trail Hartford Hartford 1.27 1.27
Shoreline Greenway Trail Madison Madison 1.66 1.68
Still River Greenway Brookfield Brookfield 1.52 1.53
Sue Grossman Trail Torrington Torrington 1.64 1.49

* due to manual counts availability, the general adjustment factor from the Air Line State Park Trail Report was applied

Short-Term IR Counters 2023

Adjustment Factors
Trail Name/Counter Location Town  short-term 2023
Charter Oak Trail Manchester Middlesex Community College Manchester 1.33
Cheney Rail Trail Manchester Middle Turnpike Manchester 1.14
Cheney Rail Trail Manchester The Mills Manchester 1.38
Hop River Trail Andover Center St Andover 1.19
Hop River Trail Manchester Colonial Rd Manchester 1.16
Hop River Trail Willimantic Kiosk Willimantic 1.51
Niantic Boardwalk East Lyme East Lyme 1.78
Quinnipiac River Linear Trail Wallingford Wallingford 1.04
River Trail New Milford North Entrance New Milford 0.73
River Trail New Milford South Entrance New Milford 1.1
Shoreline Greenway Branford Westpoint Branford 0.70
Shoreline Greenway East Haven East Haven 1.33

note: unusually low or high factors can be due to low number of counts, low usage, equipment malfunction or weather related anomalies

Short Term vs Long Term Counters

The Trail Census Dashboard displays data from counters installed  "long term" (one year or more - many continuously since 2017!) as well as "short term" (weeks to months).  Counters installed long term require regular monitoring from local volunteers, and at least four visits per year by CT Trail Census staff to download data and for regular maintenance.  With so many counters spread over the entire state, getting to all counters during just one round of visits can take several days of staff time, and hundreds of miles of travel.

With a limited number of counters, and a lot of demand for local trail use data, CT Trail Census staff use short term counts to help local trail managers better understand use on their trails.  These counts are conducted over at least several weeks to provide a good representation of hourly and daily use patterns, and comparison to similar nearby trails can allow for estimates of annual trail use.
Note: Since counters at short term count locations were installed and uninstalled on varying days of the week, and for varying amounts of time, the summarized monthly and weekly uses shown for short-term counters might not accurately represent full week or month counts.