Collection nodes - a safe, convenient place to pick up car-poolers.
This idea is not so much for improving Waze as for improving infrastructure to work better with car-pooling apps. Most cities have bottlenecks in their highway networks. This creates places that are made for drivers to find riders all in one place to reduce the number of vehicles going to a bottleneck, thus reducing congestion. My detailed proposal is based on conditions at the tunnel crossings into Manhattan, but the basic concept could be applied in many places. It is not a simple idea and I had to go into a lot of detail to explain it. I also did illustrations depicting what these might look like. You can read about it on this website: https://cross-hudsoncommutesolution.com/