Physics Problem?

A city planner is working on the redesign of a hilly portion of a city. An important consideration is how steep the roads can be so that even low-powered cars can get up the hills without slowing down. It is given that a particular small car, with a m of 1050 kg, can accelerate on a level road from rest to 22 m/s (79.2 km/h) in 14.0 s. Using this data, calculate the maximum steepness of a hill.