Car parking problem has been considered as one of the major issues in our daily life activities. This is due to the increase of the number of cars in the world. Growing the global number of cars increases the demand for parking which in turn needs intelligent and highly efficient systems, providing best practices in car parking operations management. Parking availability prediction and reserving a vacant parking spaces in congested cities are major concerns to many motorists. Therefore, this paper proposes a new smart parking architecture called Informative Smart Parking System. The proposed architecture provides motorists with advance information about parking lots availability in real-time basis. It also provides motorists with availability parking suggestions without the need to install sensors. The development of non-IoT smart parking systems will help to facilitate the smooth transition from conventional parking system infrastructure to digital transformation era which is entirely equipped with IoT. In addition, a mathematical model is provided to calculate the number of available parking spaces based on arrival time prediction. This model is a novel attempt to predict the available number of parking spaces at any expected arrival time.