Progressive’s snapshot program installs a small device into the customer’s car, and if the driver rarely has a “hard brake” (which they define as more than 7 mph decrease in speed in a second), they will “award” the customer for beng a good driver. Which, I think absolutely is A JOKE.
Suppose I drive with 35mph speed on a urban road. With my speed, if I see a yellow light at the next cross and want to take a full stop without having a “hard brake”, it will take me at least 203 feet to stop. This is assuming I have normal reaction time (1.5s) and decelerate at perfectly 7mph /s.
If I decide to take the chance and pass the cross before the light turns red, assuming the cross is 46 feet in length (four lane street) and the yellow light lasts for 4 second, I need to be within 149 feet of the cross, otherwise I WILL run over the red light.
This means, if I see a yellow light when I’m between 203 feet to 149 feet from the traffic light, then I’m screwed. I need to choose either to run over the red light or be penalized by Progressive for having a “hard brake”.
How frequent is this? Assuming the average green light duration is 30s, then I have 1.5% chance of running into this awkward situation at each cross. (Even if you drive at 30mph, it is still around 1.5% in chance.) So If I drive 10 miles per day on weekdays in a pretty busy district, I WILL on average run into 3 hard brakes per day, unless I compromise my driving safety somehow. The probability that I have zero hard brakes on a typical day is less than 5%. All these are assuming I have perfectly fine driving technique, and makes no mistake anywhere.
As I said, the “7 mph/s” definition for “hard brake” is totally a joke and basically penalize anyone who lives in cities. What is even worse is that it encourages people to take chance and run over red lights. I seriously doubt the legality of the “snapshot” program and suggest it be suspected until proved safe.