The app uses Google Maps to plan the route, so it should pick up any closures or diversions which exist at the beginning of the commute. As the app offers a fixed carpool payment system up-front based on distance and destination, there is no change in cost, and no extra costs outside of what is paid through the app will be incurred.
Remember, this is not a profit-making application and is designed to offset Driver costs (within Canada Revenue Agency guidelines) and offer a cheaper, sustainable transportation alternative to passengers.