Council considers converting Alton Hills Drive to three lanes to slow speeds and add bike facilities; public split over parking and safety

City traffic engineer Sam Bazzina and consultant Nick Graesch presented an updated traffic and safety study for Alton/Elton Hills Drive and recommended a three‑lane conversion as the safest corridor profile given existing access density and school crossings.

The study compiled updated turning‑movement counts, recent speed measurements and a 10‑year crash history. Consultants reported average daily traffic of about 9,000–11,600 vehicles depending on corridor segment and found 85th‑percentile speeds have increased since 2019, with many vehicles exceeding 35 mph on a posted 30 mph corridor. Safety analysis identified 12 segments performing worse than statewide averages and three segments above a critical crash rate.

Alliant modeled both four‑lane and three‑lane cross‑sections under existing and forecast traffic; intersections generally meet city level‑of‑service standards in both scenarios and three‑lane options increase peak travel times by seconds (10–20 seconds across the corridor in peak hours), not minutes. The consultants argued three‑lane conversions commonly reduce conflict points and crash severity, simplify pedestrian crossings by creating median refuges and make it easier to add cyclist facilities.

Public engagement produced mixed results: a neighborhood meeting, advisory committee input and an online survey (about 180 responses) showed strong interest in safety improvements but split opinion on bike lanes. The Pedestrian and Bicycle Advisory Committee favored a fully separated two‑way cycle track, while roughly two‑thirds of survey respondents opposed bike facilities on Alton Hills. Parking utilization on the corridor appears low (staff estimated <20% occupancy in many places), but residents said curbside parking matters in areas with single‑driveway homes.

Staff identified two leading alternatives for council consideration: (A) a three‑lane conversion with parking on both sides and no bike facilities (easier to implement and preserves more parking), or (B) a three‑lane conversion with a protected two‑way cycle track on one side and parking on one side (provides a continuous protected route but requires a durable barrier and additional budget for protection and signal/mast‑arm adjustments). Staff proposed returning July 20 with detailed designs, pilot/monitoring metrics (3‑year checkpoint) and cost estimates for barrier options that are plowable or removable without annual teardown.

Councilors asked for comparative crash data from previous local conversions, clarified winter parking rules (one‑side parking exemptions apply), and requested clear performance metrics if the city pilots a new configuration. No final striping decision was made; staff will provide refined alternatives, cost estimates and a monitoring plan ahead of the July council action.