I use the Waze app. Tells you your speed AND where the cops are.
GSP gave me a warning ticket once because I had new mudders on my truck. Told the officer I had cruise control on. didn't see how I could be going that fast -he was the one that noticed the new tires. Went and had the speedo checked (long before cell ph. apps), and the tires threw if off by a little more than 5 mph. Few thousand miles, and the tires "wore in"
GSP gave me a warning ticket once because I had new mudders on my truck. Told the officer I had cruise control on. didn't see how I could be going that fast -he was the one that noticed the new tires. Went and had the speedo checked (long before cell ph. apps), and the tires threw if off by a little more than 5 mph. Few thousand miles, and the tires "wore in"