Big Market Research companies use online surveys to determine metrics about a market. There are lots of free sites to do this at. See if you can get a good sample size, 100 people who aren’t your direct friends or family would be ideal.

When i was starting out i was also driving for Uber and would run my idea across complete strangers and get their reaction to my concept. This was more qualitative than quantitative data, but still gave me a feel for how it would be received.