Installed Pep Boys velocity style deer whistles on my '06 pick-up and moto. We moved to Oregon from southern Nevada last year involving 5 round trips along Hwy 95, 395, 44, 89 & I-5. About 400 miles is deer territory, some real heavy between Reno and Mt Shasta. I can't confirm the whistles "work", I never had a deer run in front of my vehicles. I did see a herd of horses look up when was approaching at a distance.