O'Fallon explains traffic-calming policy, petition process and voting thresholds

Todd Arch, assistant director of engineering, outlined how the City of O'Fallon evaluates and installs physical traffic-calming measures and what residents should expect from the petition-to-installation process.

Todd summarized the policy history (written by a resident committee in 2007 and adopted in 2008; revised procedures in 2023) and said the program uses data, not anecdote, to determine need: staff installs counters and conducts at least five days of traffic counts (including a weekend) and computes an 80-point score based on speed, volume, violation rate, proximity of schools or parks, driveway density and sidewalks. If a segment scores 80 or above it qualifies for traffic calming.

He described common measures used locally — speed dips (the prevailing treatment in O'Fallon), raised medians, traffic circles — and explained the city's reasons to prefer dips over speed humps (maintenance/plow considerations) and when other devices are appropriate.

The process after qualification includes a preliminary design, an open-house public meeting, design modification based on feedback, review by emergency services, and a mail-back ballot to residents within 300 feet of the studied roadway. The ballot requires 65% of ballots returned to be in favor for installation to proceed; council has final approval and staff performs a 6–18 month post-installation evaluation with an established removal petition process if necessary.

Todd noted the program can be costly, can shift traffic to other streets and cannot prevent reckless driving, but said it is effective at lowering average roadway speeds in many local examples. He also said demand has risen in recent years (6 evaluations in 2023, 7 in 2024, 9 in 2025 and several early-2026 requests).