Abstract Manager

Trip generation is a foundational step in traffic studies, as it makes it possible to anticipate the impact of new developments on road networks that are often already saturated. These estimates directly influence technical recommendations, mitigation measures, and broader mobility management strategies. The primary reference used in North America remains the Institute of Transportation Engineers’ Trip Generation Manual (TGM). However, questions arise regarding how representative these trip‑generation rates truly are for the specific contexts in Canada.

The TGM is built on a dataset whose quality varies considerably across land‑use categories. Although many new observations were added between 2017 and 2021, a portion of the database still relies on older studies, some dating back to before the 2000s. This creates a mismatch with current mobility conditions, especially in the post‑COVID era, where travel behaviors and modal choices have shifted significantly. In addition, the TGM provides limited transparency about key attributes such as the exact year of data collection, or the precise location of the sites studied. Several land‑use categories remain weakly documented; for example, land use 222 (Multifamily Housing, High‑Rise) is based on only 22 studies, which raises concerns about statistical robustness.

In this context, our study aims to compare TGM‑based predictions with traffic counts conducted in various sectors of Montréal and its surrounding municipalities. We systematically analyze the discrepancies between the manual’s trip‑generation rates and locally observed data, distinguishing among several types of land uses, including residential, commercial, and service‑oriented developments.

The presentation highlights the limitations of the TGM and demonstrates the extent to which Montréal‑area counts diverge from its predictions.