NDOT consultant outlines Porter Road speed‑cushion plan; neighbors question collector status, diversion and ballot rules

Jeff Hammond, a consultant for the Nashville Department of Transportation (NDOT), presented a preliminary traffic‑calming concept for Porter Road and asked neighbors for feedback at a virtual neighborhood meeting. Hammond said NDOT collected speed and volume data that showed an 85th‑percentile speed of 37 mph (meaning about 15% of measured vehicles exceeded that speed) and a daily traffic volume of roughly 4,500 vehicles, putting Porter Road close to NDOT’s 5,000‑vehicle threshold for typical speed‑cushion treatments.

Hammond described the proposal as a half‑mile project from Eastland to Greenwood (about 2,500 feet) with four sets of speed cushions spaced roughly 400–600 feet apart (an average spacing NDOT staff said is about 500 feet). He explained speed cushions are modular recycled‑rubber devices (typically six feet wide and about 10½ feet long) designed with gaps so large‑wheelbase emergency vehicles are less affected, and said cushions in practice have reduced measured speeds by about 9–11 mph in NDOT before‑and‑after data. Hammond also reviewed…