I recently decided to look into car insurance rates again to make sure I wasn't overpaying. I do this maybe every 12 to 18 months or so. Progressive Auto Insurance gave a good quote and in it I was given the option to include Snapshot. It's a device to plug into your OBD-II port in your car. It reports back to Progressive via the AT&T cell network what time of day you drive, how you accelerate and how you brake. The device will make an audible beep if you brake to hard. I've previously written about devices you can plug into the ODB-II port of you car to log and monitor data from your car, in my case with the Torque Android app. It's fun and I haven't done too much analyzing log data but I may still.
I decided to wait on changing car insurance companies but I did decide to do a free 30 day trial of Snapshot. It would give me a sense of how it works and of how much more I could save off of Progressive's rate by letting them know how/when I drive. I got two of their devices in the mail for our two cars. My question was if I could have this and my own OBD-II device plugged in at the same time. I purchased this OBD-II splitter from Amazon because with just a 30 day trial I wouldn't have time for the long boat from China. I tried it out and it works! The Snapshot device will beep when the car first starts and again if you brake too hard. I noticed that the delay from car start-up to hearing the Snapshot start-up beep took longer when I had both devices plugged in. But it did beep. I also intentionally braked too hard to make it beep at me, which it did. All the while I was using Torque to read info from the car in real time. Great!
I can't guarantee that Snapshot would always work in this situation. With or without Snapshot, my own OBD-II device was able to read about 17 PIDs/second (PID is a command/response to/from the car). The Torque wiki of bluetooth adapters lists some that are capable of up to 60 PIDs/second. Assuming 60/s is the limit of the car, this suggests to me that Snapshot has plenty of time with my own adapter attached to get the information it needs. And I bet some cars have slower computers than others (i.e. have varying PID limits) so Snapshot doesn't have a problem with a slowdown due to my adapter sharing the bus. Also great!
There's no free lunch, though. That splitter cable is long. In one car it was causing the two adapters to dangle right next to where I would put my leg when braking. This is extremely dangerous! DO NOT DO THIS! Having things in the way of safely driving your car is NOT an option. If for whatever reason this scenario was something you absolutely needed, get the help of a professional to ensure the adapters and splitter are installed safely. The same goes for using your phone while driving. BE SAFE. When I use Torque I start it logging while the car is parked and then put it away while driving. Don't compromise safety.
TL;DR: The two adapters can be used at the same time. Maybe not with better, faster OBD-II adapters, though. And safety is always first.
So I made this test in November and December but there it is. We drove to/from Idaho for Thanksgiving and I captured data during the long trips. The csv files from the Torque app look great. But what about Snapshot? Was it capturing data, too? If you go to Progressive's website, you can look at the data. Here's what I saw for those trips: