I've successfully done this as well in a smaller town. City Hall engineers sat down with me and looked at accessible routes to school, bus/train station, and the grocery store. They built 7 curb cuts; it cost the city 35K. Every time I saw someone else using those crossings for years afterwards it made me super happy. And, I could take my kid to school without going in the street, in the dark, in the rain... I don't think this works every time but it is definitely worth asking. Another interesting point I found out while going through this process, was that it takes some work for the city to find out who is responsible for particular streets and intersections (It might be a local or state transit agency rather than the city).