This study evaluated driver yielding behavior at basic- versus high-visibility crosswalk (HVC) markings on undivided major street approach legs of two-way stop-controlled intersections. The research team measured and compared driver yielding rates using staged pedestrian crossings at sites with HVCs and at sites with basic markings. Study sites were undivided two-lane roadways with relatively low speeds (25 to 35 mph speed limits) and volumes (up to 616 two-way vehicles per hour during crossings)—half with basic crosswalk markings, half with HVCs. In addition to site characteristic data (crossing distance, presence of bike lane, presence of on-street parking, location context), the study included the collection of vehicle volumes and approach speeds, which enabled statistical modeling of yielding in relation to site characteristics and driver speeds. In total, the study collected 1,188 individual observations at 32 sites in four states. The results showed that, under certain conditions, HVCs were associated with increased driver yielding relative to crossings with basic markings. The study further showed that an approaching driver’s speed and prevailing site speeds had a strong and consistent negative effect on driver yielding. Site context and other treatments present at the site had an impact, but the relationship between driver speed and yielding was robust and statistically significant across all tests. Drivers exceeding 40 mph were unlikely to yield to a pedestrian waiting at a marked crosswalk, suggesting that an agency should consider supplemental treatments to increase driver yielding at such locations.