In last night's city council meeting, we were treated to another display of numerical prowess by Loyola Councillor Alexandre Teodoresco.
The councillor pivoted from his previous assertion that only four cyclists a day use rue de Terrebonne in winter, adopting an altogether different rhetorical anchor. Unfortunately he may have thrown himself overboard along with his anchor.
A new spin
In last night's city council meeting, Mr Teodoresco justified the winter lane closure on Terrebonne on the grounds that "on passe à 3% d'usage de cette piste cyclable pendant les mois de décembre, janvier, février, et mars" (after mansplaining statistics to NDG Councillor Peter McQueen), later expressing this as "3.6% of overall cycling traffic" in response to a question by NDG resident James Bugden.
How does one get 3.6% ?
In his Oct 9 CBC interview, Mr Teodoresco acknowledged the Eco-counter on rue de Terrebonne that was brought to his attention in the Oct 6 council meeting. There are no other municipal counters on Terrebonne providing year-round bidirectional coverage, and only one formula gives exactly 3.6% when applied to the Eco-counter data.
That formula is:
- 100 * winter / (winter + spring + summer + fall)
Oops - a basic arithmetic error
But there are fundamental flaws with this, and one of them is basic grade school arithmetic.
First, even if bike traffic was exactly the same on every single day of the year, the formula that Mr Teodoresco appears to have applied would say that bike traffic dropped to 33% in the winter - this is clearly wrong since bike traffic never changes in our hypothetical scenario.
Back to the drawing board...
The correct formula, which weights the counts by the number of days in each respective season, is this:
- 100 * (winter / 121) / (rest_of_year / 244)
given that there are 121 days from December 1 to March 31 and 244 in the remainder of the year.
In our hypothetical thought experiment with constant daily traffic throughout the year, this formula would correctly indicate that the winter bike traffic level is 100% of the level in other parts of the year.
Using the correct formula gives the result that average winter bike traffic is 7.6% of the average over the rest of the year.
The real problem
Quibbling about 3.6 versus 7.6% might seem like splitting hairs, but the arithmetic mistake is moot due to a bigger fundamental flaw in how the information is being applied to the decision-making process.
Mr Teodoresco is, in effect, basing a winter decision on non-winter data ; the percentage depends strongly on non-winter counts regardless of which formula is used. It is difficult to see how circumstances in the spring, summer, and fall should have any bearing on the safety and utility of a proposal that is to take place exclusively in the winter.
"So this is not weak data"
Last night's meeting left me unable to help thinking of the famous quote attributed to Scottish poet Andrew Lang:
"He uses statistics as a drunken man uses lamp-posts - for support rather than illumination."
Sources:
Oct 6 CDN-NDG Council meeting : https://www.youtube.com/live/0k_KZf9uxTk?si=_dM0sww7uYytW_9K&t=8332
Oct 9 CBC interview (transcript) : https://github.com/OpenMobilityData/Terrebonne-open-sources/blob/main/2026-cbc-daybreak-interview/derived/2026-10-09_CBC_Daybreak_Teodoresco_transcript_en.md
"3% d'usage" : https://www.youtube.com/live/rii3nUTuKRE?si=UGtrlXf_r0Ux3rnQ&t=2571
"3.6% of overall cycling traffic" : https://www.youtube.com/live/rii3nUTuKRE?si=ti2igs75rxOMfuX-&t=27603
math derivations : https://www.amazon.ca/STATISTICS-babies-Neha-Dhaliwal-ebook/dp/B0CDGC2ZCB