Cycle network and route planning guide - NZ Transport Agency

Calculation equation
The following equation yields the best estimate of a cycling AADT:
AADT Cyc
= Count
* 1 * 1 * W
H D 7
where Count = result of count period
H = scale factor for time of day
D = scale factor for day of week
W = scale factor for week of year
If cycle count data for more than one day is available, then the calculation should be
carried out for each day, and the results averaged.
Worked example
Suppose two counts (of 90 and 165 minutes respectively) have been undertaken on
weekdays in May. The site is used by both school children and commuters. The count data
and the coefficients to be used are shown in the table below, as well as the AADT estimates
resulting from the two counts.
AM COUNT
PM COUNT
TIME 7.30 to 9.00 3.00 to 5.45
CYCLISTS 125 127
DATE 29-May-03 30-May-03
DAY Thursday Friday
H 25.5% 30.6%
D 16.8% 15.2%
W 0.98 0.98
AADT ESTIMATE 410 382
Averaging the estimates yields a cycling AADT of 396.
Recommendations
We recommend using the above equation for approximating the cycling AADT. As cycling
volumes fluctuate from day to day depending on the weather, this method should be
used with caution, and ideally the estimate should be achieved based on the average of
the results of several counts. Individual counts should be for periods of no less than 60
minutes. Counts should be of cyclists in both directions and cover at least the morning
peak period, the after school hour and the evening commuter peak. Counts during warmer
months and school terms will provide the most reliable estimates. Also take note of tertiary
calendars when planning counts. It is not appropriate to scale up counts from Christmas/
New Year holidays.
Use the Christchurch data in the absence of better local information, but take into account
any demonstrable local factors. While the data has limitations, being from a limited
number of sites in Christchurch only, it is now possible for the first time to scale up cycle
count data with some confidence.
Acknowledgement
The method was developed by Axel Wilke of Christchurch City Council, building on work
by Aaron Roozenburg (Beca Christchurch) in preparing data and undertaking some of the
analysis. A fuller description of how the method was derived is available for Axel Wilke at
Christchurch City Council. As more data is collected and the figures are refined, updated
tables will be published.
82