Public Works reports modest speed reductions, high costs in traffic-calming pilot

Public Works Director Tim Schumpert briefed council on the county's traffic-calming pilot and what staff learned since the policy's 2023 adoption.

Schumpert said the county has installed devices on three roads — one in Chapin and two near Gaston — and measured roughly a 6-mile-per-hour reduction in the 85th-percentile speeds where devices are in place. "Long story short, we've basically lowered the 85th percentile speed for people," he said. "We've got about almost 6 mile per hour reduction on those, which is not insignificant." He added that the devices have not achieved the reductions staff originally anticipated.

Schumpert outlined two device types: bolt-down units (more removable) and asphalt-built, more permanent humps. He estimated typical per-unit costs at about $7,000 for the asphalt style and about $11,000 for bolt-down units and said a three-set installation is treated as one unit; across three roads the county spent "about a $100,000 on these 3 different roads installing these." He also said spacing typically needs to be no closer than 350400 feet to be effective.

Council members pressed staff on trade-offs. One member worried about liability if vehicle damage results from county-installed features; Schumpert acknowledged claims are possible with any infrastructure on county-maintained roads. Another noted that devices sometimes reduce traffic by diverting cut-through drivers to other streets; Schumpert said a recent Hill Haven installation both lowered speeds and reduced cut-through volume.

Several council members asked whether neighborhoods could privately fund installations. Schumpert said the current policy does not specifically provide for private-public funding but the county could accommodate federally permitted or encouraged installations through an encroachment or permit process. "If a neighborhood wants it bad enough, work out a public private, relationship," one council member said, and others urged staff to craft clearer guidance on cost, maintenance, and post-installation responsibilities.

Schumpert recommended continuing installations but asked the council whether it wanted staff to explore policy changes, and to keep using a case-by-case analysis of road geometry, traffic counts and expected effectiveness. Council members asked for more data from the pilot and for clearer rules on long-term maintenance and whether the sheriff's department will augment enforcement in treated areas.

The county made no policy change at the meeting; staff said they would return with recommended changes, more cost detail and enforcement coordination.